WALNUT CREEK (KPIX 5) — If you get good service at a restaurant, you leave a good tip. But with a shortage of workers, some restaurants are making the optional tips mandatory.

At Oyama Sushi in Walnut Creek, a slip informing you of a mandatory 15 percent tip comes after you enjoy your nigiri and rolls. The owner of Oyama, Kit So, estimates she’s lost more than 10 servers to bad tipping even after raising hourly wages.

“Sometimes people didn’t leave a tip at all, “ So said.

In November, So added a mandatory 15 percent tip to every bill, so there’s enough at the end of the night to split between sushi chefs, dishwashers and servers.

“I’m okay with that–as far as not tipping correctly and this is part of their salary–I’m fine with that, “ said Oyama regular Pilar Bland.

Lined up on the counter is another reason that tipping has gotten so bad: to-go orders made through apps like GrubHub and UberEats.

So says people have gotten out of the habit of going to restaurants, but are paying tip-like surcharges on delivery apps.

“I think we should do that, too, because people come out to have dinner and we give them service and we take care of them. So, I think 15 percent is really reasonable,” said So.