.New Water Storage Design Could Pave Way for Water-Neutral Homes

A 46,000-gallon rainwater tank made entirely of stainless steel hides behind a grove of oak trees atop the highest slope on John Haskins’ 5-acre Corralitos property. If all goes according to plan, that tank and two others will make the Haskins home water-neutral, which is why he wanted to install it after so many dry years.

This winter’s historically high rain levels, however, filled up Haskins’ new rainwater storage system quickly, and have left it consistently full. Still, these storms only reassure Haskins that he’s made a good investment as he resists temptation to call the five-year California drought over—no matter what the meteorologists say.

“Nobody predicted all this rain,” he says, noting that last year’s El Niño winter was slated to bring massive levels of rainfall to California, and didn’t. And this season, a La Niña year, was supposed to be rather dry. “Weather patterns are only becoming more unpredictable.”

The tank is 27 feet in diameter, and holds enough rainwater to supply his family of four with the water they need year-round, so long as they remain frugal with their usage and cut back on irrigation during the summer.

The Haskinses hope to eliminate their impact on Santa Cruz County’s groundwater, which has been under stress from over-pumping since the 1950s.

Last year, the family used an average of 600 gallons of water per day during the summer months and 200 gallons per day during the winter, including household use, drinking water, irrigation, and filling their living swimming pool—a chemical-free alternative to the backyard amenity.

Haskins’ property is still connected to a well, which used to be the home’s primary source of water before the rainwater catchment system was built. And with the simple flip of a lever, Haskins can still draw from the well just as easily as before.

But in theory, if the Haskinses follow through with their plan to cut back on summer water use, they should have enough rainwater in the tank to shut off flow from the well year-round, something that would help out their many neighbors.

Water in the Pajaro Valley aquifer below—the Aromas Basin—has fallen well below sea level due to decades of over-pumping, causing seawater intrusion along the coast, which could permanently contaminate the groundwater source.

Haskins almost certainly won’t ever experience seawater intrusion on his property in Corralitos, but Chris Coburn, executive director of the Resource Conservation District of Santa Cruz County (RCD), says that drawing from any groundwater source in the county contributes to the overdraft problem. So by going off the water grid with his project, Coburn says Haskins has provided an “excellent example of what individual homeowners can do to help.”

Jack Schultz, a civil engineer with experience on what he calls “unconventional projects,” designed Haskins’ system—his second rainwater system in Santa Cruz County. Schultz hopes his design will inspire other locals to consider curbing their groundwater use by catching rainwater.  

Schultz built solar water heaters beginning in 1974 with his company, Solar Utilities, long before home solar use became popular in the United States. Since then, he’s worked on a variety of projects—from protecting creek banks from erosion in Scotts Valley and Aptos with redwood-log cribbing to repairing water systems damaged in Sumatra after the 2004 Indian Ocean earthquake and tsunami.

Schultz says rainwater systems designed for drinking water purposes are rare in Santa Cruz County, in part because the regulatory codes do not normally allow for them. He’s designed Haskins’ system to meet EPA requirements for water purification, which he hopes will eventually be approved for permitting in Santa Cruz County.

Regardless, the county still granted a permit to Haskins’ storage tank because his property has access to a well, and the new disinfection system is considered an addition, not the primary source of the home’s drinking water.

Schultz’s design uses three tanks, allowing for maximum capacity and purification. Rainwater that falls on Haskins’ roof runs downhill into a transfer tank and then passes through a series of filters, as it is pumped back uphill to storage and has all of the pollutants removed along the way.

The large storage tank is high on the property’s slope, allowing gravity to send the water back down to a supply tank connected directly to the home’s water pipes. On its way to the domestic supply tank, the rainwater goes through the final stages of its disinfection process.

Water districts typically disinfect municipal water with filters and chlorine, which protects against any accidental contaminants. Because Schultz’s design doesn’t use chlorine, its water runs through ultraviolet light and back into the supply tank, completely re-purifying it, about once a day.

The storage tank is also linked to a fire hydrant, and home use shuts off if the water level goes below 5,000 gallons, which gives the fire department an emergency supply in the event of a fire.

Schultz—whose son Jozseph owns India Joze restaurant in downtown Santa Cruz—thinks of Haskins as a pioneer in sustainable living, especially because the project benefits the whole basin, more than it does his own family.

Grounded Solutions

Another way to ease the groundwater problem is with aquifer recharge.

In October of last year, the Pajaro Valley Water District teamed up with the RCD and Andy Fisher, a professor of hydrogeology at UCSC, to launch their Recharge Net Metering program, the most recent step in a process Fisher has studied for years. The program provides financial incentive for landowners willing to retrofit their property to direct rainwater into the ground.

The five-year pilot program is the first of its kind in California, and aims to attract landowners whose properties are particularly favorable to groundwater recharge.

Qualifying landowners will provide upward of 100 acre-feet of water infiltration per year—roughly 32,600,000 gallons—and will receive a rebate from the district based on the amount they contribute. The program aims to serve as a model for future programs across the state of California.

The Scotts Valley Water District (SVWD) unveiled a groundwater strategy of its own last month, when it announced a recharge system at the Scotts Valley Transit Center.

Construction crews replaced portions of the concrete parking lot with permeable surfaces, allowing rainwater to percolate back into the Santa Margarita Aquifer, which provides drinking water to all of SVWD’s roughly 11,000 customers.

“The system is designed to add 1 to 1.5 million gallons of water to the Santa Margarita Aquifer on an average wet year,” says David McNair, the district’s operations manager who oversaw the recharge project. Construction is almost complete at the Scotts Valley Transit Center parking lot, and percolation into the groundwater store has already begun. “We’ll be monitoring it closely to see exactly how productive it will be.”