City ordinance requires a backflow valve on all new and newly-repaired sewer lines. But you can have a plumber add a backflow valve to your line right now. It's the best protection against sewer backups.
A backflow valve can stop sewage from backing up into your home.
Clean it periodically to keep it working.

The valve closes when water comes into it from the wrong direction.
If a clog occurs, the backflow valve will stop the sewage from backing up into your house.

If you are downhill from the sewer main, be sure a backflow valve has been put on your sewer line – especially if your house is in an older area of the city.

Even if your house is in a borderline location, installing a backflow valve may be a good precaution. Once the valve is installed, clean it periodically to keep it working right. Talk to your plumber about the installation and cleaning or call Customer Service.

Avoid future backups 

Call Water Emergency -- (405) 297-3334 -- at the first sign of a problem or before the sewer backs up. If your drains are running slow, for example, call us. Crews will come and check the lines.

Dispose of grease and fats with your trash, not down the drain. Even if you run it through a garbage disposal, grease in drains can collect and harden into a plug.

Plant trees and large shrubs away from sewer lines. Roots grow toward breaks or cracks in lines. When roots get inside the pipe, they clog it.

Never connect sump pumps, French drains or other flood control systems to your sanitary sewer. It's illegal and the debris and silt will clog your line. Call a plumber to undo illegal connections.

Make sure you have proper insurance

Sewer backups are not automatically covered by all homeowner’s insurance policies. Check your policy to make sure you are covered for damages due to sewer backups.

Remember, the City is not an insurer. The City can only pay for damages under extremely limited circumstances set out by law. Don’t assume you’re covered. You may need a special option for coverage. Talk to your insurance agent.