California Finds Collecting Rainwater Can Mitigate Drought's Impact

by | December 22, 2014

By Lisa M. Krieger

When rain drenches Mark Wialbut's mountain home, it sprouts inspiration. His vast network of gutters, pipes, tanks and filters has captured more than 10,000 gallons so far this month, with more to come_enough for his family to be self-sufficient this winter in their Los Gatos aerie.

For most Californians, rain-catching is a seasonal hobby and not practical enough to eliminate dependency on snowmelt, reservoirs and groundwater.

But for Wialbut _ and the growing number of collectors like him _ rainwater systems are enough to weaken drought's fierce grip.

"The water is used for everything," said Wialbut, a salesman at Applied Power Technology at work but a water sanitation specialist, maintenance mechanic and troubleshooting technician at home.

"It tastes great," he said. "And this morning, I took a nice long hot shower."

In the East Bay, Tony Poeck of Indira Designs reports a 30 percent revenue increase this year for sales of rainwater and "grey water" (to reuse household water) collection system equipment, design and consultation.

Several 20,000-gallon systems –– enough to supply an average family for about 115 days –– are being installed in San Francisco, Marin and the East Bay, he said.

The math is simple: For every 100 square feet of roof, 1 inch of rain yields 60 to 100 gallons of water. So if you have a 1,000-square-foot roof, an inch of rain will give you 600 to 1,000 gallons.

In places where the average annual rainfall is 12 inches of precipitation, it is possible to collect 10,000 gallons annually from a 1,500-square-foot residential roof or 700,000 gallons annually from a 100,000-square-foot commercial building, according to the American Rainwater Catchment Systems Association.

Some opponents of rainwater harvesting have argued that it deprives flow to streams and aquifers, where it is needed for wells. But proponents say it eases pressure on other sources of water, as well as helps manage storm-water runoff.

Rain that falls on his large composite roof is captured and conveyed via gutters and 60 feet of piping. From there, it empties into two 5,000-gallon tanks, fitted with microfilters, and secured on a flat gravel pad. "It was nerve-racking," he said. "I had visions the night before of them rolling and smashing into thousands of pieces."

Then, because the tanks are downhill from his home, a powerful pump sends the water uphill to a third tank, where ozone kills bacteria and any other pathogens.

Its final stop is a smaller pressure tank, designed to prevent erratic surges to his modern plumbing. Then it goes to his home, his garden and his large koi pond.

The occasional mishap _ such as a weakened pipe thread _ has caused leaks.

"It's definitely trial and error," he said. "Imagineering!"

The only frustration, he said, is its size. With so much rain this month, he's had to release thousands gallons of water deep underground. So he plans to double capacity, ultimately saving enough water to last all year long.

"We are creating a solution, like people do it all over the world," he says. "There's no water in the ground, so we get it from the sky."

(c)2014 San Jose Mercury News