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Old 03-11-09, 10:06 PM   #1
Join Date: Sep 2008
Location: SE Wisconsin
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Default Ben's DIY Graywater System

For a while, I have been thinking about some sort of graywater system.

My house uses a "holding tank", which is just to say that the waste-water from the house goes into a 2000 gallon tank buried in the backyard.

A holding tank is much cheaper to instal, but much more expensive to maintain in the long-run. That's because you have to pay somebody to empty it every time it's full.

It costs about $90 to empty. How often? Well, at my house it's about every 5 or 6 weeks. That means water cost more than gas or electricity at my house, which also means it should be a priority on my EcoRenovating.

(And no, please do not start a discussion about getting a septic tank or municipal sewer at my house. Septic tank would have to be above ground, cost about $15,000 and literally take up my entire back yard. Municipal sewer is not available, and even if it was, still costs money, although less than what I currently pay!)

Anyways, what seems to make sense is one of two things (or both!).
1) Run water to someplace other than the holding tank. (The yard or garden for example.)
2) Reuse the water inside the house before running it down the drain.

I really don't want sudsy bubbles in my side yard, and the garden is pretty far away - uphill, so lets focus on option 2.

Both of these options are considered "graywater" - water which has been used, but could still be used again for, say, watering plants. This is different from "blackwater" which is what goes down the drain from the toilet.

Speaking of toilets, that would be a great place to SEND graywater. Why do we flush our toilets with perfectly good drinking water? That doesn't make sense!

Instead, why not use water doing down the drain of the sink, the shower, or someplace else to fill the toilet tank?

I have kept kicking around the idea of using waste shower water to feed the toilet. I take a shower every day.....I use the toilet every day.....It makes sense. Both are right near each other.

HOWEVER! I am limited in space. My house is over a concrete enclosed crawl-space. (Think a full basement, which is only 22 inches tall!) That leaves me little room for a basement water tank or ease of accessing any sort of filter system.

Today, it dawned on me that the clothes washer would make a better option for a graywater source to feed the toilet.

Here's why:
Crawl space access is 2 feet away from the washer.
Laundry drain is VERY easily accessable
Water storage tank could be located in laundry room instead of in crawl-space.
Laundry puts out rather "clean" dirty water - no chunks of bar soap or long hairs!

The only real disadvantage is that the laundry room is farther away from the toilet than the shower is. But that's not a big deal, it just means I need more pipe. I think the extra expense of 20' of small-diameter pipe is worth it.

In the above photo, you can see that there is some space between the utility tub (on the right) and the clothes washer (in the middle)
There's still about 8" between the the washer and the dryer (on the left.)

If I moved the washer as far to the left as I could, I think the space between the utility tub and the washer is big enough to hold a custom water tank. The washer uses about 20 gallons per load. I think I could fit a 40 gallon tank in, but maybe not a 60. How big is a gallon? I might have to do some 3-dimensional math to figure out how many gallons fit in a space 30 inches deep by 30 inches tall by X wide.

The downside to this is that we DO shower every day, but we do NOT do laundry every day! Still, that would mean that all the water we use for laundry would be "free" as it saves us from flushing other water down the toilet drain!

Please expect this project to be "long-term", as I still need to Ecomod my electric car to 144 volts, convert my pickup truck to bio-diesel, build my wife a greenhouse, get off gasoline and corn syrup........ The list goes on!

All positive ideas and comments welcome.


PS: Also in the photo, you can see the trap door that allows me access to the crawl-space. That's the only way to get under the floor to work on plumbing or anything else I would build down there.


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Last edited by bennelson; 03-11-09 at 10:08 PM.. Reason: ps
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