Rainwater can be collected from roofs into plastic water tanks for storage during dry periods.
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The cost of water, increased environmental awareness and bouts of drought have many businesses and homeowners looking at finding sources of water outside the municipal systems they used to rely on.

When customers want to go off the grid, there are two common options: rainwater collected from roofs and/or driveways, or graywater, which comes from showers, laundry and other daily uses.

Choosing a water source.

Art Elmers, district sales manager for Netafim USA, says there are three questions you need to look at when choosing a water source:

  • What do I have available?
  • How much water do I need?
  • What am I allowed to use?

For residential customers, Shawn Crawford, national sales manager for Rainwater Management Solutions, determines the water use, how much a homeowner wants to spend and what sort of footprint they want to have.

Rainwater Management Solutions has been designing and installing systems for more than 20 years. Right now it does about 80 percent commercial systems and 20 percent high-end residential installations.

The size of the property is usually the determining factor for both rainwater and graywater collection systems. For rainwater, the roof or other collection area will determine the supply while a graywater system’s supply depends on the number of people producing wastewater in a home or business.

The irrigation demands are also part of the equation. A property in Ohio, where rainfall is steady, won’t need as large of a tank as a home in Arizona that only gets 15 inches of rain per year.

“Graywater is kind of similar. Graywater is going to be how much water is being consumed a day from our collection point and then how much is going to be used from the (irrigation) system daily,” Crawford says.

And be sure to look at local ordinances. Different levels of treatment will be required depending on your customer’s location.

Some states, like Missouri and Mississippi, don’t require any disinfection while others, like Washington, D.C., are stricter. In some areas, graywater can’t be used for irrigation at all, and in others, rainwater collection is illegal.

According to Crawford, it’s important to determine whether the system is sprinklers and sprayers or subsurface.

Spray irrigation will most likely need more treatment than subsurface since the water distribution is less controlled.

“So there are a lot of things that drive that (decision) and there is no clear-cut answer as to the best way to go,” Elmers says. “It’s going to vary according to ZIP codes and statutes, what’s available and how much you need.”

Bring in the backup.

Almost all alternative water systems will require a backup system with potable or well water. Rainwater Management Solutions will either run the domestic water line directly into the reclaimed or rainwater tank or run that line downstream directly into the irrigation line.

“I don’t think there’s virtually any system that will simply run off of graywater or rainwater collection,” Elmers says. “You’ll always have to have an alternate water source.”

Rainwater is Elmers’ first choice since it’s cleaner, but customers often end up using both. “The graywater we’re adding to the tank dilutes the rainwater because the rainwater is typically your better quality unless you have really bad pigeons in the area,” he says.


While chemical, biological and UV treatment are all options, the key is keeping the system low-maintenance, Crawford says.

Rainwater systems require a filter change every six months. Graywater units, which Rainwater Management Solutions only has available commercially for now, require a change four to six times a year. However, different local governments may require more frequent checks.

One complaint of alternative irrigation sources is the price of a system. But, the systems have their benefits, especially in drought-stricken areas.
Photo courtesy of Rainwater Management Solutions

Drip irrigation will require more treatment for particles than a sprinkler or sprayer systems since the openings are so much smaller. But both systems need a self-cleaning filter.

“The thing about any filter you put in is typically your rainwater and graywater has more solids in it than potable water. So a filter in a potable system – you wouldn’t have to clean it more than once a year.

“But if you’re putting that same filter in a rainwater or graywater system, you’re going to maybe clean it once a week,” Elmers says.

Customer education.

While graywater and rainwater are cheaper alternatives to potable water, it’s important to show customers how to use the resource responsibly.

“You’re spending a lot of money to hold that water,” Elmers says. “It behooves you to use it smartly. The more water you can save on the tail end by applying it, the lower you can drop the demand level. You’re only using the water that’s needed, so you’re maximizing how long your tank will last.”

The hardest part of the job is getting customers to understand the systems, Crawford says. Different components and model numbers can get confusing when something breaks.

For example, one of Crawford’s customers called because his pump wasn’t working. The problem was that a float switch had gotten stuck while he was doing some maintenance.

“Little things like that happen and he understood it after that,” Crawford says. “So we work really hard to educate our customers and we’re working even harder to do that even more. We’re still not there yet.”

Elmers says the biggest complaint he hears is the price of a system. However, the benefits of a cheaper, or free, water supply has its benefits, especially in drought-stricken areas.

“When there are drought restrictions, guess who’s still allowed to irrigate,” Elmers says.

“You, because you’ve got your own water. You’re like a squirrel; you’ve kept the acorn for the winter. So you’re able to irrigate when others can’t.”