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Check Valve and low flow – functionality issues

Wednesday, July 18th, 2012
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While blogging about low flow, I should mention its impact on our check valve.

We decided in the very early days of the project to protect the basement from flooding and sewer back-ups with a check valve. We have a blog post with illustrations that walks you through our rationales and the decision.

 

Last year, when we needed the protection from the check valve, we did not get it, because I had failed to properly maintain it. Rather than closing and thus preventing water from backing up into the garden apartment, it got stuck in an open position.

Since then, I have been very diligent with my check valve maintenance. I inspect it monthly and also when we have big storms coming our way.

What I noticed during the inspections is that solids build up behind the valve gate. So much so that they potentially could prevent the gate from closing.

That problem is easily solved. I have a little metal strap that I use to fixate the valve gate in a fully open position. I go into the bathroom, flush the toilet and dump another 5 gallon water bucket down the drain. That typically flushes all the solids out of the system and down the main sewer.

I understand that the buildup of solids is not typical, but rather is caused by the low flow fixtures in the garden unit. Conventional plumbing fixtures, including a conventional toilet, would produce enough flow and velocity to keep the system flushed and “clean.”

That begs the question if the check valve was the right decision? I would argue that, yes, it was the right decision out of the options we had available to us.

To keep our check valve operational, I flush the system on a regular schedule.

Does that not defy the water conservation goal? Yes, it somehow does, but only until I have access to sump and/or cistern water for the flushing. It will be easy to do, it allows me to exercise resource conservation with the low flow fixtures in the garden unit, and gives us the flood protection we need.

But one should be aware that there are strings attached when combining a check valve with low flow fixtures.

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Wasteful low flow

Monday, July 16th, 2012
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We have this wonderful Caroma low flow, dual flush toilet in the garden apartment.

The short flush only uses 0.8 gallons, and the long flush a mere 1.28 gallons. These are probably the lowest flow rates for a toilet with a non-pressurized tank.

It gets even better. On top of the tank is a small sink. After flushing, the toilet tank is refilled with the water from the small faucet. We can wash our hands and automatically reuse that water for the next flush. This allows us to double the water mileage.

This simple but beautiful resource conservation recently went down the toilet (pun intended). We noticed that water from the tank was leaking into the toilet bowl. It wasn’t much, but it was leaking 24/7, completely negating the impressive water conservation aspect.

I emptied the tank, lifted it off the toilet and removed the flushing mechanism. The owners manual helped me to identify the diaphragm seal that supposedly keeps the water in the tank until one flushes.

 

Once I had the diaphragm seal removed and could take a closer look, I noticed a small, perfectly circular bump, like a little outgrowth. It wasn’t stuck to the seal but rather seemed to be a part of it. Very strange indeed and the obvious cause of the leak. We had the toilet in operation for just over one year and I have no idea where that bump came from.

The owner’s manual listed a part number for the diaphragm seal, which helped me to order a replacement for $6.00 online. Three days later, I installed the new gasket seal, and … no more leaking! No more water conservation down the toilet. No more wasteful low flow.

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Spatially challenged

Sunday, April 8th, 2012
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Back in January, I described two useful plumbing gadgets. One of them was the the on-demand hot water circulation pump. I had to install it in a pretty tight space, in the plumbing wall.

Well, it turns out that I have to re-install it, because that day, I was somewhat spatially challenged.

Typically, the pump is installed under a sink, laying on the bottom in the vanity or base cabinet.

That orientation does not work in the plumbing wall, because I only have 5 1/2 inches to work with. The dimension of the pump, however, is 7 1/2 inches from front to back.

It got much more promising once I turned the pump up by 90 degrees. The pump depth is only 5 1/4 inches. Just about slim enough to fit into the plumbing wall.

I was happy with that solution — happy that I found a way around the spatial constraints — and I installed the pump accordingly.

It turns out that there is a good reason why the pump is typically laying on its side, with the cylinder cartridge in a horizontal position.

The cylinder cartridge contains the pump motor. The pump motor must be in a horizontal position for smooth operation and longevity’s sake. If the cylinder cartridge with the motor is in a vertical position, the motor has difficulties to maintain the same rotation. It may get out of whack and become unbalanced and noisy, and it eventually may break down.

How could I have known? To begin with, I could have followed the installation instructions more closely. Not only that, but we have a number of other water pumps in the utility room. And they are all installed with the cylinder cartridge in a horizontal position. Let’s call that a hint!

I was of the opinion that I did not have the room in the plumbing wall to position the cartridge horizontally. But all it took was to turn the pump by 90 degrees counter clockwise.

I am telling you – spatially challenged!

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DWV details

Tuesday, January 31st, 2012
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Let’s leave the potable water plumbing behind and circle back to the drain-waste-vent (DWV) system.

You may recall reading about the rationales and details of the 1st and 2nd floor DWV system and looking at the installation description all the way to the roof vent.

With everything installed and documented I can now compare the schematic layouts and diagrams to the real thing.

To keep us in compliance with the Chicago and State of Illinois plumbing code, all the DWV plumbing is connected to the city sewer. But we structured the plumbing for future separation of the greywater from the blackwater without the need to open any walls. At that point we would collect, filter and store the greywater for later reuse.

Greywater stack

The future greywater system begins in the basement at the drain water heat recovery (DWHR) unit, which we placed at the bottom of the greywater stack.

The horizontal leg that currently connects the DWHR to the sewer can in the future be replaced with a small greywater collection tank that holds a sump pump and has an emergency overflow connection to the sewer.

Atop of the DWHR is a double wye, which connects to the primary greywater source, the 1st and 2nd floor showers. One leg serves the 1st floor bathroom floor drain, the second leg connects to the 1st floor shower drain, while the third leg is set aside for the 2nd floor bathroom.

If we follow the greywater stack from the basement up to the 1st floor, we find the shower drain vent that ties into the floor drain vent, effectively forming the greywater vent stack.

The leg we set aside to drain the 2nd floor bathroom continues towards the ceiling where we placed a simple wye. One branch serves the 2nd floor bathroom floor drain while the other branch connects to the 2nd floor shower drain.

Once we continue to follow the greywater stack from the 1st floor up into the 2nd floor, we can identify the floor drain and shower vent that connect to the main vent stack from the 1st floor. The stack is turning up, over and around the corner towards the main sewer or blackwater stack.

Blackwater stack

The four inch diameter blackwater stack is located in the plumbing wall with two vent lines to either side.

The two inch pipe to the left vents all of the basement plumbing. The kitchen sink vent also ties into this pipe, while the kitchen drain connects to the blackwater stack.

To the right of the stack is the two inch vent for the 1st floor toilet. The bathroom lavatory vents into this two inch pipe, while the drain connects again to the blackwater stack.

Looking at the plumbing wall from the other side, we see the 2nd floor toilet connection and vent towards the ceiling.

Moving up to the 2nd floor, the kitchen and lavatory drain are identical to the 1st floor layout, with both draining into the blackwater stack.

A little up we connect the plumbing wall vents. On the right we have the kitchen sink vent and vent from the 1st floor. To the left we have lavatory vent, the vent from the 1st floor and the 2nd floor toilet vent.

Toward the top is the vent stack connection from the showers and floor drains, before the stack turns over and up through the roof.

The only item visible on the roof is the five inch vent section of the stack.

Even though the bathroom lavatories are connected to the blackwater stack, we have a future plan for reusing the greywater from these sinks. There are simple and small filtering and storage systems, that would fit under the lavatory. The collected water would then be used for the toilet flushing,

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Plumbing installation – useful gadgets

Tuesday, January 24th, 2012
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Here is a little more information about two useful gadgets in our plumbing system.

The previous post lists the rationales behind the hot water routing and makes mention of a hot water circulation pump. Let’s start with that.

On-demand

I was referred to a product that would help us to cut down on energy and water waste. It is an on-demand hot water pump by D’MAND®Systems.

Typically, the pump is installed under the fixture that is farthest away from the hot water tank. It is activated with a push button or motion sensor and begins to prime the hot water line. In that process hot water is brought close to each fixture along the hot water line, providing almost instant hot water.

Graphic by: http://www.gothotwater.com/

The most common location for the pump is under a sink, which makes the installation very easy. It is shipped with the needed fittings for a quick retrofit. The package includes two flex lines to connect to the existing hot and cold water lines under the sink.

Our fixture at the end of the hot water branch is the shower, not a sink. That means that I will have to install the pump into the plumbing wall.

We did provide a hot and cold water stub to which we can connect the pump. But I am not ready to trust those stainless steel flex connectors. Not in a plumbing wall where access will be difficult.

Instead I opted for a hard plumbing connection. In other words, I used copper pipe and fittings to connect the pump.

The pump will be plugged into a GFCI outlet in the plumbing wall. Once that outlet is connected, we can pressurize the plumbing system and test-run the pump.

Pressure reducing valve

The pressure reducing valve in the shower riser is the second item I should point out. I gave this nifty gadget some mention in a previous post, but it may be
worthwhile to bring it up again.

The reason for the pressure reducing valve is the shower head, or to be more precise, the desire for a reliable 1.5 gallons per minute (gpm) low-flow shower head.

The one product we found to work really well, in that you get a stream of water that is powerful and does not feel like a trickle, is the Oxygenic® BodySpa® SkinCare™ Shower Head. But it is rated with a 2.5 gpm flow rate – at 80 psi water pressure.

To guarantee a low flow rate of 1.5 gpm for our showers, I’ll have reduce, control and stabilize the water pressure, as can be seen in the graph below.

The graph doesn’t seem to be entirely accurate, nor the dial settings on the pressure reducing valve. We found out when we were field testing what pressure would really get us the desired 1.5 gpm.

Once we had dialed the pressure reducing valve down to 25 psi, the shower head delivered the targeted 1.5 gpm low flow rate.

Should we decide to change the shower head in the future, which may require us to increase the water pressure, we can simply adjust the dial and thereby the pressure on the pressure reducing valve.

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Plumbing – energy conservation (part 2)

Wednesday, August 17th, 2011
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We covered the issue of structural waste in a plumbing system. We minimized the energy losses (maximized the energy efficiency) within the plumbing system. But we still will have to wait for hot water, although it may only be for a few seconds. This is where behavioral waste comes into play.

Managing behavioral waste

What exactly is behavioral waste? Say you want to take a shower. You turn on the tap and get distracted while waiting for hot water (you check your e-mail, make a phone call, you name it). Before you know it, too much water and too much thermal energy went down the drain (pun intended).

There is a quick fix for this scenario, the ladybug shower head adaptor, a product by Evolve.

It appears that behavioral waste is primarily driven by the amount of time we have to wait for hot water. The shorter the time-to-tap, the lower the potential for behavioral waste.

Here are the strategies we have covered so far that result in a reasonable time-to-tap:

  1. Compact and efficient layout of the plumbing system: Keep the pipe runs as short as possible.
  2. Material choice: If possible, use tubing with the least potential for initial heat loss.
  3. Pipe insulation: deliver hot water effectively to the point of use.
  4. Pipe sizes: minimize the tubing size and thus the volume of water in the plumbing system.

(Almost) instant hot water

If, despite these strategies, you still have to wait too long for hot water, or you cannot implement some of the strategies, you may want to look into an instant hot water solution.

Metlund has a system on the market that meets our water and energy conservation goals.

It is a small circulation pump that is installed at the farthest fixture in the system. The pump is activated with a push button, upon which it begins to draw water from the hot water line. The pump turns off the moment is senses a slight temperature rise in the water temperature.

The cold water the pump has drawn until now is either pushed into a dedicated return line to the hot water storage tank or pushed into the cold water line, thus no water is wasted.

Because the pump is located at the farthest fixture in the system, all other fixtures located along the branch will get primed with hot water up to the twigs. The water volume in the twigs is so small that hot water should arrive within one cup (see also table in previous post) – or almost instantly.

We are seriously considering to try the Metlund system. It would improve our overall water and energy conservation. Those savings will at one point pay for the equipment.

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Plumbing – energy conservation (part 1)

Monday, August 15th, 2011
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In a plumbing system there are two types of energy consumption that come to mind.

  1. Kinetic energy (pumping to move water around), and
  2. Thermal energy (for domestic hot water).

Let’s ignore pumping at this point, because turning cold water into hot water is the real energy consumer we need to worry about.

Material choice matters

Copper tubing is often the chosen and/or required material in a plumbing system. Copper is also known as a pretty good heat conductor, which can lead to inefficiencies. There is an initial energy loss when hot water flows through copper tubing due to the thermal energy transfer from the hot water to the copper pipe.

Using potable water system PEX tubing would result in lower initial heat loss as PEX has inferior heat conducting properties when compared to copper. The problem is that some building codes won’t permit PEX tubing in plumbing systems, as it is the case here in Chicago.

Insulation matters

No matter what the choice of pipe material, all pipes ought to be insulated to deliver as much hot water with as little heat loss as possible to the point of use (such as a faucet).

How much pipe insulation is needed? The Chicago Green Homes Program requires “standard flexible pipe insulation or better [with an] R-3 [insulation value in] conditioned space.” My friend and hot water guru Gary Klein has another helpful rule of thumb.

He recommends that at the minimum the thickness of the pipe insulation equals the thickness of the pipe diameter. For instance, half-inch tubing is insulated with pipe insulation that has at least a half inch wall thickness, three-quarter-inch tubing is insulated with pipe insulation that has at least a three-quarter inch wall thickness, etc.

Managing structural waste

As an introduction into structural waste, I should mention the three different phases that occur when we use hot water:

  1. Phase 1 is the delivery phase, where the hot water is delivered to the point of use.
  2. Phase 2 is the use phase (taking a shower, washing the dishes…), and
  3. Phase 3 is the cool down phase, once we are done using hot water. The hot water sitting in the plumbing system begins to cool down.

I mentioned in the previous post the importance of an efficient plumbing layout and concluded with a description of a structured plumbing system with a trunk, branches and twigs. This does not only contribute to material conservation but also contributes to energy conservation.

Pipe runs are kept short and pipe diameters are kept small in an efficient and compact plumbing system.

  • The shorter the pipe runs, the less heat from the hot water is lost to the copper pipes during the initial hot water delivery phase (as explained above).
  • The shorter the pipe runs, the smaller the hot water volume sitting in the pipe, minimizing structural waste during the cool down phase.
  • The smaller the pipe diameter (within reason), the smaller the hot water volume sitting in the pipe, minimizing structural waste during the cool down phase.
  • The smaller the pipe diameter (again, within reason), the less water and energy is lost to behavioral waste, while waiting for hot water to arrive at the point-of-use.

The last two items mentioned here need some more unpacking. Let’s start with the former:

Smaller is better

Smaller pipe sizes, as laid out above, minimize the volume of water in the plumbing system. This becomes important in energy saving terms, because we lose less thermal energy during the cool down phase.

pipe-sizes

To understand what difference the pipe size, and subsequently the pipe material can make, let’s look at some data from my friend Gary Klein. He looked at various pipe materials and various pipe sizes that are in use today. The table below lists the linear feet for each material at each size that hold one cup of water.

The smallest I can go, as per the current code, is copper type M at a 1/2 inch diameter. 4.7 feet of that copper tubing would hold one cup of water. 3/8 inch tubing would be more proportionate to our low flow fixtures. That means I almost could triple the length of tubing holding one cup of water if I would be allowed to use potable water system PEX tubing.

No such luck! I can dream about the associated energy savings, but I cannot tap into them.

Less is more

We established that low flow fixtures are a good water conservation strategy. The less hot water is used (the less water there is to heat up) the more energy is conserved. Low flow fixtures are thus an excellent energy saver.

Hidden in all this is a potential conflict with our water conservation goals. How so? Low flow fixtures can result in a longer time-to-tap. Because we reduce the flow rate, the hot water will take longer to arrive at the point of use. As a result we waste clean, cold water down the drain, while waiting for the hot water to arrive.

The solution to this problem brings us back to the material conservation strategies – to smaller pipe sizes. We established that we can reduce the pipe sizes in a plumbing system that uses low-flow fixtures. Let’s put it this way:

lower flow = smaller water volume to deliver = smaller pipe sizing

As a result, we reduce the probability of a longer wait for hot water as the pipe size is proportionate to the low flow rate. We also reduce energy loss during the cool down phase, as mentioned above.
Water is only wasted in plumbing systems with low flow fixtures and no decrease in the pipe sizes.

There is another good argument for smaller tubing in efficient plumbing systems: No one that I know likes to wait for hot water, which gets us into what we call behavioral waste.

This will be a nice topic for the next post.

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Plumbing – material conservation

Wednesday, August 10th, 2011
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I got a little distracted by the recent weather events, but let me return to the fresh water plumbing system in our house.

In a recent post, I listed three major objectives: water conservation, material conservation and energy conservation. We covered water conservation, which leads us to the issue of material conservation.

Compact layout

An efficient — or better — a compact floor plan leads to material conservation in a plumbing system. Go into any building constructed around 1900 and you quickly see what I mean. The water heater is typically placed right next to the plumbing wall in the basement, which continues all the way up to the top of the building. The kitchen and bathroom are placed back to back alongside the plumbing wall. This layout reduces the amount of pipe runs needed by placing the water heater and fixtures as close to each other as possible.

Because our house was build in 1902, we are blessed with a compact floor plan, where the kitchen and bathroom are separated by the plumbing wall. Sadly, this efficiency is not very common in our over-sized contemporary homes, where bathrooms and kitchen are often scattered through all four corners of the building.

We won’t need much copper tubing for the new plumbing system, because we can keep our pipe runs as short as possible. This is good news. Copper has a pretty large carbon footprint. The less we have to use of it, the better.

Also, copper tubing and the associated fittings are expensive. With that in mind, material conservation pays off – literally.

The water conservation impact

Let’s mix material conservation with water conservation, and we’ll get an interesting result.

We established the benefits of low-flow fixtures. An added benefit of low-flow fixtures is that less water is delivered to the point of use (shower, faucet, toilet, you name it). This in turn allows us to reduce the pipe sizes in the plumbing system.

Well, only up to a point controlled by the Chicago Plumbing Code, which has not yet quite caught up with the arrival of water conservation strategies and low-flow fixtures. The smallest pipe size allowed is 1/2 inch. With some low-flow fixtures, though, a pipe size of 3/8 inch would do the job.

As a matter of fact, look under your kitchen and bathroom sink. There you will find the faucet water connectors (flexible tubing that connects to the faucet), which in most cases is 3/8 inch. That is OK according to code. You just can’t have 3/8 inch tubing in the wall. Too bad!

The tree analogy

I mentioned my friend Gary Klein, the hot water guru, in my recent post. He explained to me how to manage and minimize pipe sizes in our plumbing system by using a tree analogy.

The pipe from the water heater in the basement to the 1st floor and 2nd floor is called the trunk (trunk line), which also has the larges diameter (3/4 inch to the 1st floor and then 1/2 inch to the 2nd floor). The trunk has to convey the largest water volume out of all pipes in the system, thus the larger diameter.

Connected to the trunk line, we have branches (at 1/2 inch diameter) that deliver the water to the basement plumbing, 1st floor plumbing and 2nd floor plumbing respectively.

Connected to the branches, we “could have” twigs (at 3/8 inch diameter), with each twig servicing one outlet, i.e. the bathroom faucet. I say “could have”, because code won’t allow us to use 3/8 inch tubing. So, instead of twigs, we have the branches at 1/2 inch diameter servicing each fixture.

Smaller tubing sizes means also overall increased friction. To reduce pressure loss, potable water systems PEX tubing would be ideal. It requires less fittings (such as elbows) and has softer bends and turns, which minimizes pressure losses. But again, our Chicago Plumbing Code is standing in the way, only allowing copper tubing for potable water systems.

To reduce pressure losses with copper tubing, Gary Klein  insists on using the uncommon long sweep 90 degree elbows, rather than the typical hard 90 degree ones. He is also a fan of using 45 degree elbows instead of 90 degree ones, where possible.

There is another benefit to using small diameter tubing – an energy conservation benefit, which I will get to in the next post.

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DWV Part 2 – details

Thursday, June 23rd, 2011
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We need to structure our DWV system in a way that allows us to separate the blackwater from recyclable greywater. That requires scrutiny of all waste water sources in the building and to assign them to the one or the other category.

Discharge from the toilet contains human waste and as such is blackwater. This is easy.

But what about the kitchen sink and dishwasher? Waste water from these sources is typically considered greywater. We are, however, concerned about the contamination potential through food scraps.

To keep things simple and to have peace of mind, we made the decision to discharge waste water from the kitchen sources with the blackwater and not recycle it.

Drain water from the shower and bathtub, on the other hand, is a perfect source of recyclable greywater. So is the water from the bathroom sink, except that there will be very little of it considering our low flow faucets at 0.5 gpm.

Last but not least, there is the washing machine in the basement, the waste water from which is also a good greywater source.

Let’s see how the categorizing of these sources fits with or impacts the DWV layout.

Structuring the sewer

The entire basement DVW plumbing was dictated by flood prevention concerns. We solved the problem by separating the basement DWV from the other floors and protected it with a check valve.

This solution has one drawback. The layout prevents us from collecting or recycling greywater from the basement fixtures. (The exception is the washing machine.)

The basement DVW system as well as the upstairs bathroom layout determined the location of the main sewer stack (or blackwater stack) that will serve the 1st and 2nd floors. It will carry the waste water from the toilets, kitchen sinks and dishwashers.

The 1st and 2nd floor bathroom showers and floor drains are connected to a secondary stack, which is a dedicated greywater stack. Right now this secondary or greywater stack is connected to the basement DWV system to comply with the Chicago plumbing code.

However, once the collection and recycling of greywater becomes permissible, we will be ready for it. We can insert a small collection tank with a little sump pump at the bottom of the stack. The small collection tank would still have an emergency connection to the basement DWV plumbing (as is the case now) in case of a power outage of failure of the sump pump.

The sump would pump the geywater from the small collection tank to a gravity filter from where it would flow into the final storage tank.

That takes care of everything, except the waste water from the bathroom faucet, which is some distance from the greywater stack, but right next to the blackwater stack. We probably could figure out how to connect it to the greywater stack. But is it worth considering the faucet flow rate of 0.5 gpm and the miniscule amount of waste water produced?

We always could go with an off-the-shelf greywater system, which is installed under the sink and routes the filtered waste water into the adjacent toilet tank for flushing. That is, once these systems are permitted by the Chicago Plumbing Code.

The waste heat layer

This exercise got us to think about solutions for greywater recycling. But there is another waste product that we didn’t want to ignore:  the waste heat in the greywater.

To recapture the waste heat we installed a drain water heat recovery (DWHR) system.

Going a few posts back you can read up on how we scrutinized the sources of waste heat, weather it comes from a greywater or blackwater source, and determined how it would impact the DWV layout.

We ended up placing the DWHR unit at the bottom of the greywater stack, just above the future collection tank.

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DWV Part 1 – rationales

Sunday, June 19th, 2011
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Let’s go back in time for the next posts. I would like to dissect the plumbing system some more. A good starting point is the drain-waste-vent (DWV) plumbing.

I described the PVC to CISP connection and the DWV basement installation. But I said little about the rationales and layout other than the discussion about the new CISP sewers and the check valve location.

The moment we look at what goes down the DWV plumbing, sustainability creeps into the picture. As the name suggests (drain-waste-vent) we are talking about draining waste water. Although, not all waste water is equal.

Blackwater…

… is the term coined for the waste water we flush down the toilets – water that contains fecal matter and urine. Blackwater requires processing, typically in a waste water treatment plant, where pathogens and organic matter are removed. Only then and once disinfected is it safe (from a human health and safety aspect) to release into the environment.

There are a number of other, ecologically sound, smaller and/or decentralized blackwater treatment options such as constructed wetlands and the ecological engine, which have been widely researched and published.

Greywater…

… is the watered down cousin of blackwater. By definition it cannot contain human waste.

Greywater typically originates from the sinks, showers, bathtubs and washing machines of our homes. Because it carries lower levels of contaminants, it has a lower health risk.

As such, greywater can be recycled and reused. Typical applications for recycled greywater are landscape irrigation and indoor reuse such as toilet flushing. Outdoor use, and more so indoor use, may require some level of filtration.

Policy potential

We know about, and often practice, recycling – extracting another use out of a resource rather than letting it go to waste (pun intended).

Greywater is a resource that has recycling potential, given the right plumbing layout. Rather than having one DWV system that drains everything, it can be structured to separate blackwater from the recyclable greywater.

There is one minor problem, though. Our plumbing code in the city of Chicago does not allow the reuse or recycling of greywater, point blank. The Uniform Plumbing Code prohibits the use of greywater indoors.

I don’t think it takes a visionary to figure out that, given increased pressure on our natural resources, the current policy must expire sometime in the future.

Anticipating the policy change, we would like to avoid opening up walls to get to and modify our DWV system. Instead we would like to proactively structure our stacks and sewers for easy adaptation of greywater collection once it is permissible.

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