The age-old practice is making a modern comeback.
Heavy rain, heavy runoff and drainage systems overwhelmed by water are familiar sights this winter. Now, some Bay Area water districts are hoping residents will start catching and using that rain.
Juan Fuentes was one of first people to join San Francisco's pilot program.
"We're harvesting water," he says.
The rain water flows off his roof into a downspout then into containers under his deck.
"It's going into this main barrel here and then it transfers to these other two barrels," he explains.
The three big barrels hold 210 gallons each. When they fill up, "The water will overflow and then it will come down this pipe and come down, and go into these smaller barrels which are like 45 gallon," Fuentes says.
Fuentes has barrels tucked all over his yard. Screen filters keep out leaves and insects. The system will store about 1,100 gallons to water the garden when the dry season starts.
"I have no idea so far how long it will last," he says. "I'll know after this summer."
Fuentes got big discounts on the supplies for his system because the city Public Utilities Commission is trying to encourage people to give rain catching a try. It has a double benefit. First, of course, it saves water. Second, it keeps excess water out of San Francisco's sewage treatment system.
"Here on a rainy day, you could get hundreds of millions of gallons of storm water coming through to be treated. And, in the event of a really large rain event, the system could become overwhelmed," says Sarah Minick with the Public Utilities Commission.
If a lot of people start collecting rain, it could make a big difference.
"The more storm water that we keep out of our sewage treatment system, the more capacity we have in our system," Minick says.
The Marin Municipal Water District is also encouraging rain catching. One big concern there is that when rain drains off streets, it picks up oil and other pollutants that then flow into creeks. More than 150 people showed up at an event in Mill Valley to learn how to collect rain and how to store it.
There is a wide range of rain harvesting systems available, from a few barrels to heavy-duty underground tanks. Manor School in Fairfax is putting one of the systems to use.
8-year-old student Sophie says, "It can hold 3,000 gallons of rain water."
The water is piped underground to a faucet where the kids fill up containers to water the school garden. It all works with gravity. There is no electricity needed.
"It's full of water right now," explained third grade teacher Laura Honda, banging on a tank. "I don't know if you can hear that, but you can just tell from the pressure that it's full."
Most rain-catching is for outdoor use, but Leigh Kimberg in San Francisco put in a much more ambitious system when she remodeled her house. She started with a metal roof.
"You can collect rain water on any type of roof, but metal is ideal. It's very slippery and drains all the water," she says.
Downspouts lead to tanks in the garage. Kimberg can store 2,500 gallons of water there, but it is a tight squeeze.
"I can fit my car in here," she says. "If I don't pull it in just right, I have to climb out the car window."
Pumps send the rain water back up into the house to flush toilets and clean the family's clothes.
"I try and time major loads of laundry to do during rain storms," Kimberg says.
She says the permit process to get all the equipment installed was tough. She is not sure the exact cost because it was done along with a major remodel, but outside systems are a lot cheaper and easier, and many who have tried it like it.
"Everyone that watches this channel, just please know and tell their friends to save water and that'll just help the earth," Sophie says.
The cost of rain-catching systems can vary from less than $100 to many thousands. Several Bay Area agencies are offering financial incentives, even for using very small systems.
Written and produced by Jennifer Olney