Simple Greywater Systems to Support Fruit Trees

Greywater is an excellent source of water to support trees and shrubs, and unlike rainwater, is available year-round. Greywater is untreated wastewater from laundry, showers, baths, or lavatory sinks (toilets and kitchen sinks are excluded). Using greywater from laundry does not require a permit so it is readily accessible in many situations, such as residential settings where the laundry machines are in the garage near an outside wall. Institutions and other multi-person dwelling sites can sometimes also provide accessible laundry greywater when laundry machines are in a common location for multiple dwelling units or people. In this case, there is the opportunity to utilize greywater produced by multiple people to irrigate a shared resource such as an orchard. Greywater can’t be used for veggie beds because of the potential health hazard of the greywater contacting the food. Fruit trees, berries, grapes, and even perennial veggie crops such as tree collards can all be irrigated with greywater. Many non-food plants can also do well with greywater although many native shrubs may not need supplemental irrigation.

We recently completed a laundry greywater installation for the staff laundry at Camp Stevens in Julian, California. There are three high-capacity washers in this facility which we estimate use between 17.5 to 20 gallons per load with a 4.7 cubic foot volume. The total usage is estimated at 30 loads per week or between 520 – 600 gallons. We installed diverter valves and irrigation for two of the three washers – one goes to the fruit tree orchard and the other goes to the almond tree orchard. The third washer may go to a new planted area yet to be determined.

The beauty of this system is that it is a low cost way to save a lot of water because the parts are inexpensive and once the indoor plumbing is done, most of the outside work — running pipe and digging basins — can be done with volunteers. Each of the basins has an an adjustable valve to balance the flow and also to make sure that areas that need more or less water can be adjusted appropriately.

In this setting, the weather can be quite variable, so when it is raining or snowing, the diverter valve at the washer can be turned to the septic system to avoid overwhelming the trees. Not only is the initial installation straightforward but also the maintenance is easy to follow. Using greywater for irrigation involves the users because their laundry habits must be more mindful to make sure the greywater production is beneficial for the trees. For example, it doesn’t work if everyone decides to wash their clothes on the same day!

Dwelling On Carbon is mainly focused on urban ecology with polyculture native seed mixes but is also committed to supporting local food production – both with pollinator attracting seed mixes as well as using on site water such as greywater and rainwater. We are doing simpler greywater systems such as laundry only or gravity shower systems so that these projects can be low cost and utilize volunteers for the installation. Similarly, we are more interested in passive rainwater harvesting using raingardens and swales than complex systems with rainwater storage tanks and pumps. When more complex systems are appropriate, we will work with Catching H2O Inc, our former partner.

We are planning another laundry greywater system for the staff laundry at Deer Park monastery in Escondido, California. On a recent visit, I was very happy to see the completion of the pumped shower greywater system for the new monk’s quarters – which I had planned and designed while still working with Catching H2O. This system utilizes all of the showers and lav sinks and pumps them to several zones including fruit trees along the road and shrubs as a privacy screen along the dormitory back wall. When we add the staff laundry system, the capacity for food production for the monks, sisters, and visitors will increase greatly based on an estimated 400 gallon per week supply. Stay tuned to hear about this project!!