Water District 19’s three commissioners unanimously approved a policy last week allowing homeowners to develop small rental units on their property without having to obtain an additional water hook-up.

But homeowners will have to submit an engineer’s report that shows they can serve both their home and a rental without exceeding the equivalent use of one share, said Steve Haworth, who chairs the board.

“It’s not perfect. It’s not foolproof. … But it’s a small step toward … putting us in conformity with the rest of the county,” he said.

Under the district’s current policy, those customers who want to develop what’s called an accessory dwelling unit have to obtain an additional water share from the agency — tough to come by because of the district’s long-standing moratorium on new shares.

The new policy, which goes into effect Jan. 1, means a handful of homeowners will be able to develop such units without going on the district’s lengthy waiting list. Haworth said he expects no more than 10 homeowners a year will  take advantage of the new rule. “We’re not talking about hundreds of new buildings,” he said.

The issue has garnered concern over the years because of District 19’s ongoing water shortage. But Haworth said that conservation measures as well as new water sources have led to a slight surplus, enabling the shift in policy.

“If it’s a sudden flood and we’re giving out more water than we thought, we could change it,” he added.