It was raining and Judy Adler had a broken gutter. What could have been a simple repair turned into an effort to capture rain and use it for her backyard pond. Since late 2009, Adler has collected up to 11,000 gallons of rain annually at her Walnut Creek home. “This is doable,” she said. “This is Tinker Toy stuff.” More people could follow in Adler’s steps under a bill in the California Legislature. The proposal, which would encourage homeowners to collect rainwater, could make its way onto the 2018 statewide ballot.