Frequently Asked Question
These FAQs and answers are compiled from ReWater’s experience with greywater irrigation since 1990.
PROBABLY NOT, for the following reasons:
- If your home sits on a slab, it’s not cost effective to cut into the slab just to reuse greywater. We’ve never seen a slab cut just to reuse greywater.
- If you have a raised foundation but the master shower or other regularly-used shower/tub is on the top floor, that greywater is already connected to a toilet and turned into sewage before the pipe goes down the wall. It’s not considered cost effective to tear out walls just to reuse greywater.
- Because a complete greywater system requires both a filter unit and unique underground drip irrigation, you will have to replace your sprinkler system. That’s not cost effective if your irrigation system is already working properly.
Caveats: Some unique situations mitigate those factors, such as…
- You were already going to cut into your slab at the exact location as needed to divert your greywater as part of a major remodel AND you need a new irrigation system.
- You were already going to tear into those exact walls and exact plumbing as part of a major remodel, AND you need a new irrigation system.
YES. Laundry is 25% of all greywater. There are virtually no plumbing hassles when capturing only clothes washer water. Take the J-hook on the discharge tube from your clothes washer currently on the downspout behind your washer and move it over to ReWater’s tank inlet, or a pipe draining into that inlet. There, attach ReWater’s tank.
Note that you must attach only a ReWater irrigation package to a ReWater filter package if you want a system guaranteed to work. Our emitters don’t clog from the microscopic matter in even finely filtered greywater that combines with water’s inherent minerals to create “scaling” on the inside of pipe and tubing. In 2-5 years, that scaling flakes off and the “scales” flow into our traditional emitters’ orifices and fatally clog them.
ReWater’s systems have been working for real people like you for over three decades because all our components are made especially for untreated greywater. No other company comes even close to that.
If you want a real irrigation system, YES. A pump allows you to irrigate uniformly, it can push water laterally or uphill, and is needed to operate irrigation solenoid valves.
NEVER, for two reasons. First, it’s illegal in every state to spray untreated greywater into the air due to the possibility of human pathogens becoming ingested by somebody walking by at the time, or those pathogens running off into surface waters for possible human ingestion. Second, old greywater on the surface smells bad. At best, it smells like dirty laundry. At worse, it might pond and turn putrid. In underground drip, you can’t smell it.
NOT FOR LONG. Even after you filter untreated greywater, there are still microscopic solids and the minerals found in the source water. All that stuff combines to form what are called “scales” on the insides of pipes, valves, and tubing. These scales flow downstream and clog conventional drip emitters of every make. It’s not a matter of if they will clog, but when they will clog.
If somebody tells you differently, ask them to show you an untreated greywater drip irrigation system that’s been working properly for longer than 5 years that isn’t a ReWater system. They can’t. What they will invariably show you is either treated greywater from an extremely expensive filter costing a fortune in energy and maintenance, or municipally-treated “reclaimed” i.e. “recycled” wastewater that cost the city a fortune to produce.
There is now a section in some state greywater codes that allows treated greywater to be used for toilet flushing or sprinklers. The legal definition of “treated” means a method that kills 100% of bacteria, virus, coliphage, and other pathogens, and removes suspended solids down to 100 microns. Treatment is an expensive endeavor.
Far worse, the accepted test for treatment systems, NSF 350, doesn’t require real greywater and the fake greywater they use fails to include hair and lint, the leading cause of clogs. Put another way, greywater systems certified under NSF350 don’t work with real greywater.
NO! Greywater is less salty than municipally-treated “reclaimed” aka “recycled” wastewater, which isn’t too salty for the vast majority of plants. Modern HE (high efficiency) washing machines require HE laundry products that rely on enzymes to loosen debris. It doesn’t matter which HE product you use.
For acid-loving plants that should be grown in the tropics rather than the arid West, you might want to add gypsum to the soil or “liquid gypsum” periodically to the greywater itself.
Not unless you overwater them. Drought-proof vegetation is genetically accustomed to receiving little water during the hot months, but all plant life needs some water throughout the year. Try running your greywater valves in drought-proof zones just once a week. To keep from losing greywater, alternate the drought-proof zones so greywater is going to different valves each day.
YES. If installing a new fescue lawn, install a matrix of ReWater’s proprietary emitters beneath it. Lay fescue sod on top of it, and surface irrigate that sod to establish the lawn’s roots in the soil. Once those roots are established, they will find the greywater underground and no longer require surface irrigation.
YES. Today, most jurisdictions don’t require permits for clothes washer-only systems unless there’s a pump involved. They do require a permit if a drain line is cut to capture greywater.
The difference between a system being “legal” or not is whether you have a permit.
Permits for ReWater’s systems are obtainable in every jurisdiction in California and in most Western states. Various local permit jurisdictions have various permit processes, but with a ReWater system and a “legal site” (which usually means a site with sufficient landscape to irrigate) you can almost certainly obtain a permit. We offer a code compliance form with each purchased system to expedite the permit process.
A “legal” greywater irrigation system uses greywater via an approved underground irrigation method (except in Arizona). It does not matter if the greywater is run through the most expensive filtering method on the planet or through ReWater’s relatively inexpensive filter system.
With underground irrigation, you don’t have to worry about a treatment system failing and leaving untreated greywater on the surface for kids to play in, animals to drink, or to contaminate other water sources.
ReWater has been in the greywater irrigation business since 1990.
In 1992 we successfully sponsored this nation’s first state greywater irrigation law (AB3518) right here in California. We tirelessly worked with numerous legislatures and virtually every local, regional, and state building, water, and environmental health agency and NGO in California concerned about building safety, water, and wastewater impacts to arrive at the state code.
We have since worked with countless private and military architects, engineers, contractors, landscape architects, and landscapers to help thousands of people with greywater irrigation.
The ReWater® System is the only system that has been proven to work with greywater for over three decades.