jonp
09-05-2021, 10:33 AM
When we bought our old house the line for the washing machine and kitchen sink ended up being a pipe into the backyard. We found this out when I noticed a pool of water on the ground. We tried a leech system but the soil type is clay so the size just didn't work and after a couple of years and some research I decided to try a mulch pit system. This type is approved for use in California so should be good all over the country. My area does not have zoning. You may have to attend a few meetings and educate the local board on this system but I don't think you will have a problem. By now there is much information online about them.
Here is a picture of it in a nutshell
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After looking around I followed a system developed in California which uses a system of pits with mulch to distribute the water. Here is a nice overview http://www.rhynelandscape.com/2013/01/20/15-landscape-sustainability-wastewater-reuse/
My system looks like this mulch basin in a series although due to the clay substrate my buckets are over 1ft above the bottom of the pit not 4in. If you have good drainage you may be able to get away with a 1-2ft pit. Mine are about 3ft.
288290
How I did it. First I figured out how much gray water would go into the system to size the basins. I took the washing machine complete cycle and figured 2 loads per week for us and then added the kitchen sink. This system is separate from the bathroom septic. Know the difference between black and gray water, you only want gray water. Some systems recommend not to include the kitchen sink due to food particles and chemicals but since we were going for a compost system we added it and switched to homemade castile soap for washing dishes and homemade laundry soap. We are very careful to not put any chemicals down the sink.
Knowing the gallons entering the system I went to the USDA soil maps to find the soil in my area and the permeability or how much it drained. https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm
With this information in hand I figured the volume size of pit I needed and sized it accordingly to let it drain between loads. I also added as volume the outlet pipe from the house as a back up and pit upstream as an emergency in case the bottom pits didn't drain for some reason which turned out to be a good thing. The beauty of this system is that you can add as many in a line as needed if the first doesn't work or you want to spread it out.
Here is a dug pit. I used as a surge "tank" a 5 gal bucket with holes drilled into it. The inlet pipe can have a T from another farther upline. In fact, this is the last in a series of 3 pits that I dug. In the bottom you can see the clay. The size of the pit is highly dependent on the soil type. The pipe is laid on a 1/4in per foot slope for drainage and is larger than recommended as I didn't know how many pits I would put in.
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The bucket with drilled holes
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Standard mulch I filled it with. You can use wood chips, mulch etc but not too fine as you need the drainage. I found the regular mulch used around trees and flower beds to work. Use natural not colored black, red or whatever.
288293
Filled pit. Notice the wooden cover on the bucket. I left it visible for this picture. You want to cut off the top of the bucket and have a wooden or stone cover to check the bucket every once in a while just in case. We had no problems. The cover is actually under an inch or two of mulch
288294
The mulch pit is dug out once a year and the mulch is replaced. The compost is put into the garden. You can test it for acidity and add lime or fertilizer accordingly. On the left is the year old mulch from the pit, on the right the new mulch. You can see how black and broken down it is, there is no smell. Looks like high dollar compost.
288295
The system works great. I planted a few shrubs around it and some flowers. The constant water has them growing fine. I did add a second pit downstream from the main one and am thinking of a third. You can add as many as you want. Total cost was a pick up truck of mulch, pvc pipe with connections and some hard work digging a trench for the line and the pit. The old buckets I had in the garage. Covers from scrap wood off the deck.
Here is a picture of it in a nutshell
288289
After looking around I followed a system developed in California which uses a system of pits with mulch to distribute the water. Here is a nice overview http://www.rhynelandscape.com/2013/01/20/15-landscape-sustainability-wastewater-reuse/
My system looks like this mulch basin in a series although due to the clay substrate my buckets are over 1ft above the bottom of the pit not 4in. If you have good drainage you may be able to get away with a 1-2ft pit. Mine are about 3ft.
288290
How I did it. First I figured out how much gray water would go into the system to size the basins. I took the washing machine complete cycle and figured 2 loads per week for us and then added the kitchen sink. This system is separate from the bathroom septic. Know the difference between black and gray water, you only want gray water. Some systems recommend not to include the kitchen sink due to food particles and chemicals but since we were going for a compost system we added it and switched to homemade castile soap for washing dishes and homemade laundry soap. We are very careful to not put any chemicals down the sink.
Knowing the gallons entering the system I went to the USDA soil maps to find the soil in my area and the permeability or how much it drained. https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm
With this information in hand I figured the volume size of pit I needed and sized it accordingly to let it drain between loads. I also added as volume the outlet pipe from the house as a back up and pit upstream as an emergency in case the bottom pits didn't drain for some reason which turned out to be a good thing. The beauty of this system is that you can add as many in a line as needed if the first doesn't work or you want to spread it out.
Here is a dug pit. I used as a surge "tank" a 5 gal bucket with holes drilled into it. The inlet pipe can have a T from another farther upline. In fact, this is the last in a series of 3 pits that I dug. In the bottom you can see the clay. The size of the pit is highly dependent on the soil type. The pipe is laid on a 1/4in per foot slope for drainage and is larger than recommended as I didn't know how many pits I would put in.
288291
The bucket with drilled holes
288292
Standard mulch I filled it with. You can use wood chips, mulch etc but not too fine as you need the drainage. I found the regular mulch used around trees and flower beds to work. Use natural not colored black, red or whatever.
288293
Filled pit. Notice the wooden cover on the bucket. I left it visible for this picture. You want to cut off the top of the bucket and have a wooden or stone cover to check the bucket every once in a while just in case. We had no problems. The cover is actually under an inch or two of mulch
288294
The mulch pit is dug out once a year and the mulch is replaced. The compost is put into the garden. You can test it for acidity and add lime or fertilizer accordingly. On the left is the year old mulch from the pit, on the right the new mulch. You can see how black and broken down it is, there is no smell. Looks like high dollar compost.
288295
The system works great. I planted a few shrubs around it and some flowers. The constant water has them growing fine. I did add a second pit downstream from the main one and am thinking of a third. You can add as many as you want. Total cost was a pick up truck of mulch, pvc pipe with connections and some hard work digging a trench for the line and the pit. The old buckets I had in the garage. Covers from scrap wood off the deck.