Grey Water Collecti...
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Grey Water Collection for laundry and shower water

Posts: 37
Eminent Member
Topic starter

Hello ?? Does anyone have a grey water collection for their shower and laundry water? Curious if they installed themselves or if they hired someone do help them. Any contact information(for STX), advise, tips and tricks or links would be greatly appreciated! My husband and I are interested in having grey water collected for laundry and shower water to have a dip system to water outdoors. We already use earth friendly soaps and understand it is important to avoid different kinds of soaps and such for a grey water collection. We also think this would be very helpful for the septic system to be making better use of this grey water and just a win-win all around. Any feedback on this topic would be great! 

Posted : September 14, 2020 4:11 pm
Posts: 203
Estimable Member


Grey water collection systems have limited viability in existing construction here because many of the homes have concrete floors that the drain pipes are encased in. The floors would need to be cut, re-plumbed and refinished. There are some home that have floors where the plumbing is accessible, but the cost of separating the black and grey water would still be high in most homes.

Separate systems could be designed into new construction, but it's still very expensive (plan on $5-10k+ minimum depending on size and complexity of plumbing system).

An alternative that is more common is a small separate collection system for an outbuilding or porch roof that isn't included in the home's existing rain catchment system.

I actually finished installing a small (200 gallon) system today to collect water from a porch roof where my solar panels are installed. It cost me less than $300 including the tank and took a couple of mornings to level a spot, frame and fill a gravel pad (200 gallons will weigh about 1,600 pounds full) and install the plumbing.

Conceptually, it wouldn't have taken much longer to install an 800-1,000 tank and would've cost about $1,500-1,800 with the larger tank. If you install a tank near (but lower than) your cistern overflow, you can plumb the overflow into the tank to help keep it toppped off during the rainy season.

A similar concept may be applied for other hard surface areas (like concrete driveways) as long as the topography of the lot works and you don't have cars that leak fluids that might be harmful to plants.

I'm not trying to rain on your idea, merely point out a less expensive and more common alternative for your consideration.

As always, best of luck!


Posted : September 14, 2020 11:19 pm
Alana33 reacted
Posts: 2935
Famed Member

Because my laundry room is located in the pump room, I was able to run a pipe from the washer that is not connected to the rest of the plumbing. We don't "collect" the gray water (although we could), but, we are able to redirect the outflow here and there. Its amazing how quickly the plants grow with all the phosphates or whatever is in the gray water. It did make the bananas taste soapy, but, I never liked those types of bananas anyway.

Posted : September 15, 2020 8:09 am
Exit Zero
Posts: 2460
Famed Member

In the late 70's I lived in an old house in STT that had a grey water tank collecting water from the driveway, it was plumbed to flush the toilets - above the grade enough to gravity feed the toilets - saved on cistern water and worked w/o water pump power.

As I understand septic systems and could be absolutely wrong here but I thought the grey water addition to black septic water helped considerably in the breakdown process.

Posted : September 15, 2020 12:42 pm
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