Use of Greywater in California
May 18, 2015, L. Culp
Legal use of greywater in the United States has been slow in coming.
Building/Plumbing Codes for greywater use are gradually changing throughout the
United States, however considerable building/plumbing code amendments need to be
done before everyone in the United States can legally use greywater.
So far, greywater reform in the southwest has been most active with California as the
first State to establish emergency regulations for use of greywater to the 2007 California
Plumbing Code. The current 2013 California Uniform Plumbing Code, (UPC), has the
latest greywater regulations and also has provisions for the capture of rainwater.
Arizona, New Mexico and Texas also now have building/plumbing code provisions for
the use of greywater.
The City of Ridgecrest and Kern County currently permit greywater systems per the
2013 California UPC and local agencies are permitted to adopt enabling ordinances that
require more stringent code requirements. As an example, the City of Chula Vista has
adopted a greywater ordinance which makes it mandatory for all new residential
structures to stub out for grey water systems. The City of Ridgecrest has not waived
any permitting requirements or adopted more stringent code requirements as of this
writing.
The current 2013 California UPC has three chapters that regulate greywater, recycled
water and rain water capture. Ch. 16 covers greywater usage, Ch. 16A covers recycled
water and Ch. 17 covers rain water capture.
The 2013 UPC Ch. 16, “Alternate Water Sources for Non potable Applications” is most
applicable to greywater systems. There are four types of greywater systems defined
and regulated in the 2013 UPC. The four systems are identified as, “Clothes Washer,
Simple, Complex and Treated Greywater Systems”. All of the systems are eligible for
new and existing residential, commercial and institutional structures.
The “Clothes Washer System”, (AKA Laundry to Landscape) systems require no
permit. It is important to review the California UPC, Chapter 16 code section for clothes
washer systems as there are 12 requirements to be followed. The clothes washer
systems are the easiest and most popular greywater systems in a laundry to
landscapedirect
system. Greywater is diverted from the washing machine and routes it to mulch or
growing basins around plants, trees or bushes. It can be expected to divert 40 gallons of
water per load from top loaded washing machines and 10 to 25 gallons per load from
front loaded machines. Many of the clothes washer systems can be installed without
the need to alter existing plumbing. A diverter valve is installed on the washing machine
drain hose. One inch tubing is then connected to the diverter valve and is routed from
the laundry room outside to the mulch or growing bed. The washing machines internal
pump moves the water through the diverter valve and one inch tubing out to the mulch
or growing basin typically without any additional pumps to flat or downward sloping
sites. The mulch or growing basins are growing beds for the plants, trees or bushes.
They are simply dug out deep enough to provide room for greywater to spread out
around the plants and to prevent greywater from running off or pooling at the surface
where children or pets could access it or mosquitos could breed. This greywater system
typically costs $75 to $200 for installation if you do the work yourself. If you hire a
professional, the work could cost up to $2,000.
The UPC defines “Simple Systems” as any system more than a clothes washer
system that diverts less than 250 gallons per day. Simple Systems require a plumbing
permit to be issued. A site plan and plumbing plan are required to be reviewed and
approved by the local agency. The soil condition for the mulch or growing basin must
also be evaluated for soil permeability and for sizing of the basin. The local agency does
have the discretion to waive the permit process by adopting an enabling ordinance.
“Complex Systems” are very similar to simple systems. The UPC defines “Complex
Systems” as any system more than a clothes washer system or complex system that
diverts more than 250 gallons per day. Complex Systems also require a plumbing
permit to be issued. A site plan and an engineered plumbing plan are required to be
reviewed and approved by the local agency. The soil conditions must also be evaluated
for soil permeability and for sizing of the basin. The local agency also has the discretion
to waive the permit process for this type of system.
“Treated Greywater Systems” have greater flexibility for allowable uses. Treated
greywater systems are the only system that will permit greywater to come to the ground
surface by using drip systems. Other permitted uses for treated greywater are for pool
filter backwash, swamp coolers, toilets and urinals. A permit is required with no local
agency ability to waive the permit process. Greywater systems require filtration and
disinfection equipment. The permit may be issued upon the review and approval of an
engineered plan for the system.
General Greywater Rules
i. Please keep in mind that the California UPC greywater codes are complex and
are updated every 3 years. Always check the current California Plumbing Code
and any local plumbing code requirements before purchasing or installing a
greywater system. Internet reference materials may not be current or applicable
to local plumbing code requirements.
ii. Before using greywater in your yard, there are a few precautions to be aware of.
One is that when you use greywater, you’ll want to choose natural soaps that
break down in the environment and won’t harm plants. Stay away from cleansers
with bleach or other toxic ingredients. Avoid sodium, chlorides, oils and boron,
which are bad for plants and soil.
iii. Always maintain a minimum of 2-inches of mulch over the greywater in the basin.
Avoid direct contact with greywater. Clothes Washer Systems often contain
small amounts of bacteria that come from your body onto the clothes being
washed. Always divert Clothes Washer System greywater to the sanitary sewer
system if laundering heavily soiled clothing with fecal matter, oily, or chemical
substances.
iv. You can use greywater on edible plants, but only fruit trees or crops such as corn
or raspberries, where the edible crop is off the ground. You may not use
greywater to irrigate root crops.
v. Never use water from toilets, dishwashers, or sinks with garbage grinders. The
discharge from these plumbing fixtures are considered as sanitary waste water
and often referred to as black water. Bacteria along with potential pathogens are
associated with sanitary waste water.
vi. Never allow greywater to pool up or run off of the property. Make sure you know
the permeability of the soil to make sure the greywater will soak into the ground.
vii. Remember that all greywater systems will require monitoring and maintenance.
The more complicated or complex the greywater system is the more expensive
and will require a higher level of maintenance.