Reinstall the washing machine to irrigate your yard instead of sending precious fresh water to the sewer.

What exactly is grey water? Domestic wastewater from washing machines, bathroom sinks, showers and bathtubs is considered "grey" because it is only slightly polluted and poses a small health risk. As long as you just put biodegradable products into the sewer, grey water is absolutely safe for irrigating plants. Kitchen sink water is technically considered grey water, but because it contains grease, it usually requires additional treatment before it can be used for irrigation.

In contrast, black water—the stuff you flush into the toilet—needs to be strengthened before it can be reused in the landscape. This is not a viable (or legal) DIY project.

There are some simple ways to recycle grey water-we have listed some here-but every time you want to irrigate, they need to be swayed back and forth with buckets or other forms of manual labor. There are also high-tech methods, but these methods require serious pipeline knowledge and substantial financial investment. The washing machine method is somewhere in between-anyone with basic household tools and good mechanical skills can do it on weekends. It will give you a few hundred dollars in supplies.

The washing machine is equipped with a pump to drain waste water from the washing machine and into the sewer. The brilliance of this system was first developed by Art Ludwig of Southern California Oasis Design Company, which uses the built-in pump of the washing machine to distribute waste water through an underground pipe system to irrigate individual plants around the yard. The water flows into the mulch pots around each plant, where the roots can be exposed to moisture.

This design is most effective for watering fruit trees, berry bushes, edible vines and other large permanent plants. Irrigating a lot of small plants (such as flower beds, lawns, and annual vegetables) is useless.

Authorities across the country are increasingly accepting grey water systems, especially in water-scarce areas. Most gray water systems require a permit (usually a licensed plumber) to install, but the washing machine system is unique in that in five states-California, Arizona, Texas, and New Mexico, It is clearly legal for the homeowner to install it without a permit. With Wyoming-and some negotiations with the local construction department, assembly may be approved in most places (although permits may be required).

Municipalities tend to be more relaxed in how to adjust the gray water system of washing machines, because this method does not change your household plumbing, and the gray water is always kept underground, thereby eliminating any health risks. However, please consult the local government before proceeding. The Graywater rules for many states other than the five states mentioned above can be found here.

Step 1: Calculate the size of the system

Before you take out your tools, pick up a pencil and paper to determine how many plants you can irrigate. Engineers have detailed methods to perform such calculations, but this is not necessary for our purposes. For each batch of laundry you wash every week, plan to wash 1 to 2 fruit trees, 3 to 4 berry bushes, 3 to 4 edible grape vines, and 6 to 8 smaller perennials (such as roses, Lavender or Artichoke).

These guidelines are based on 20 gallons of water at a time, which is a typical feature of most washing machines. However, it is best to check your user manual to understand the exact water consumption of your model and adjust your plan accordingly (compact and water-saving machines may use half of that amount).

Also, please consider your soil conditions. If the soil is sandy, irrigation water will run away quickly; on the contrary, drainage is poor in heavy clay. If the drainage is very poor, sprinkle the waste water on twice the recommended plants. In extremely sandy soils, halve the number of plants to ensure that there is enough water for their growth.

Finally, use common sense to calculate the irrigation needs of individual plants. A newly planted fruit tree only needs a small part of the water of a large mature tree. Drought-tolerant species such as olives and figs require much less water than water lovers such as blueberries and asparagus.

There is no need to be too scientific about the calculations-if in doubt, it is best to overwater with this system, because the covering pit is like a sponge, allowing the roots to absorb the water they want and minimizing the risk of drowning plants.

This image shows how to connect the irrigation pipe to the plants you want to water. Credit: Andrew Chahrour, clean water components.

The power of the washing machine pump is not very large, so assuming that the terrain is more or less flat, the plants to be irrigated should be within 50 feet of the machine. A network of hoses buried in ditches under the soil will transport water to each plant. Trenches can move up and down on moderate uplifts and descents in the landscape, but they should not directly go uphill. (50 feet does not include any distance that the pipe runs down the slope to reach the planting area, because gravity will affect this part).

Starting from the outer wall of the home closest to the washing machine, dig a shallow (2 to 3 inches) ditch until the nearest plants to be irrigated. Stop the ditch on the edge of the plant’s “drip line”—directly under the outermost leaves and branches—and dig a ditch from there to the drip line of the next plant, to the next plant, and so on.

Then dig a trench approximately 10 inches deep and 8 inches wide around the drip line of each plant. Another option for smaller plants grown in rows is to dig a straight trench along the edge of the drip line on one side of the row (maximum length is about 12 feet). The ditch will be filled with mulch to absorb grey water.

Lay a 1-inch HDPE flexible pipe (usually called polyethylene pipe) in a shallow trench, cut it and insert barbed "Ts", "elbows" and other fittings if necessary. Extend the ½” tubing from the 1” main line to each deeper groove, leaving a few inches of tubing extending into each groove. Fix the joint with a hose clamp.

The strength of the washing machine pump can only push water through 10 to 12 irrigation points at a time. If you want to irrigate more plants, use a three-way valve to divide the pipe network into two areas. The valve should be placed in the valve box so that you can operate it manually.

The 1-gallon plastic pot provides an easy way to keep the mulch in the trenches surrounding each plant away from the outlet of each pipe so that water can flow unimpeded. First, cut off the bottom of the pot. Then drill a 1 ¼ inch hole on the side about 2 inches above the bottom of the pot. Fill the bottom of the trench around each plant with 4 inch thick sawdust (compacted with feet). Slide the flower pot over the end of the tube in each ditch with the bottom of the flower pot facing up so that the top of the flower pot rests on the mulch.

Then fill the remaining grooves around each plant with sawdust. Use concrete stepping stones as the lid of each pot. Cover the pipe in the shallow trench with soil, leaving a few feet at the end of the house so that it can be connected to the washing machine.

Locate the flexible drain pipe behind the washing machine and remove it from the rigid "standpipe" that discharges the wastewater into the sewer or septic tank system. Use a 1” barbed male connector and hose clamp to connect the flexible drain tube to the 1” three-way valve. Use 1-inch diameter PVC pipes and fittings to connect one side of the valve to the sewer riser. Configure the pipes as needed so that the valve is close to the wall near the riser and is at least a few inches higher than the height. washing machine.

Select the location where the pipe passes through the wall and connects to the outside pipe. Use a 1/4 inch drill bit to drill a test hole in the wall to ensure that there are no studs, wires, or pipes behind the wall. Then drill a 1.5-inch hole in the wall. (Another option is to run the pipe through the floor and through the exterior wall of the basement crawl space to run outdoors).

Pass a 1-inch diameter PVC pipe through the wall from the open end of the valve, leaving approximately 2 to 3 inches of pipe protruding to the outside of the wall. Use the 1-inch pipe straps on both sides of the valve to support the horizontal pipe and secure it to the wall.

Attach a 1" PVC "T" fitting to the open end of the pipe outside the wall. The open end of the fitting is vertical. Use 1 inch diameter PVC pipe and fittings to connect the bottom of the T joint to the polyethylene on the ground Pipe. Cover the last piece of polyethylene pipe with soil.

Connect a 1-inch diameter PVC pipe to the top of a T-joint that is long enough to be higher than the height of the indoor three-way valve. Connect the air intake valve (also called "automatic vent"??) to the top of the pipe (this device prevents the odorous air from circulating back into the house through the washing machine). The sealed pipe passes through the holes of the external grade caulk inside and outside the wall.

*Use Teflon tape on all threaded joints. Glue the non-threaded fittings and PVC cement together.

Unless you use multiple irrigation zones, the system will run on its own. In this case, you need to turn the three-way valve in the valve box once a week outdoors. Just divide the total number of loads you run each week into two groups. After completing the first set, turn the valve to irrigate another area for the rest of the week.

The covering in the trench will slowly decompose and settle. Once a year, shovel out all the mulch every few years and replace it (spread the old mulch around the plants). As plants grow (especially trees), you may also need to regularly increase the diameter of the cover trench.

The three-way valve next to the washing machine allows you to divert the grey water to the sewer standpipe during heavy rains or during maintenance, instead of entering the irrigation system. This is also useful if you wish to use bleach in the washing machine occasionally.

These are just general guidelines. For more information on using this method in various situations, gray water system supplies, troubleshooting suggestions and guidelines, please refer to the San Francisco Gray Water Design Manual, Oasis Design, Clean Water Components, and Gray Water Action.

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Can I pour my grey water into the rain bucket? Then use the tap at the bottom to fill the watering can as needed?

Great article, thanks for your help! Another question...Dishwasher water can also be used for irrigation. It seems crazy to pour "clean" water into a septic tank. Thanks Jeff

I appreciate this article. We live in arid regions.

I appreciate this article. Very useful for my functional business!

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