Can I require tenants to pay for a home warranty? Should I?

[George Nyquist]

I work for a small real estate management and development company in San Francisco, CA. We only manage our own portfolio. We are also always building several projects to add to our portfolio using our own long-term skilled workers. However, anytime a tenant has a problem in their building, I have to pull my skilled builders to respond to a service request which throws off the development arm's productivity. My question for you all is, can I have a tenant pay for a home warranty as condition of their lease? Does anyone know if it violates the rent ordinance in some way?

Any feedback or ideas would be greatly appreciated.