Sewage, not drinking water

Backwater valves in Aurora

A backwater valve is meant to stop sewage from flowing back into the building. It is not the backflow preventer on a drinking-water or irrigation line. Buying the wrong device does not solve the backup you have.

What it does and what it does not

If the city main surcharges, a valve on your building drain can close so sewage does not enter the lowest fixtures. It does not clear a clog in your own lateral. It does not replace a broken pipe. In Aurora, if the break is on your service line, you still maintain that line to the tap. A valve downstream of a collapse does not fix the collapse. Camera first: sewer camera, then repair if the pipe is broken.

Plumber working on pipes at construction site — **Diagnostic planning:** Accurate problem identification on residential piping prevents unnecessary digging and costly contractor mistakes.

Lakewood's sewer graphic, for its north Lakewood city customers, shows a backflow prevention device that shuts to keep sewage out of the house, and it says the Colorado Plumbing Code requires that kind of device for some properties. It also shows a sewer relief valve and cleanout that can send water to the yard if the main is blocked. Those are Lakewood's drawing for Lakewood's city sewer, about 8,000 customers, not a map of every district and not an Aurora ordinance. Do not install from the drawing. Ask a plumber whether this building is one of the "some properties," and ask the inspector.

Not a potable backflow assembly

Irrigation and fire lines use backflow preventers so yard water does not enter the drinking supply. Different test, different plumber skill, different utility letter. If a water district wrote you about a test on a lawn assembly, you are not on this page.

Plumbing fittings, shutoff valves, and equipment layout — **Infrastructure standards:** Understanding city utility boundaries and code requirements ensures sound plumbing decisions for local properties.

Questions to settle first

Will a backwater valve fix a broken lateral?

No. It can block sewage from coming back in during a main surcharge. It does not open a collapsed or rooted pipe. If the camera shows a defect on your Aurora service line, you still own the repair to the tap. The valve is an add-on, not a substitute.

Is this required on every Aurora house?

This guide will not say that. Lakewood's city graphic says the plumbing code requires a sewage backflow device for some properties, and that graphic is for the city's own north Lakewood customers. Aurora's wastewater page does not repeat that sentence. Ask the inspector for the address.

The utility sent a test notice. Is it this valve?

Probably not. Test notices are usually for drinking-water backflow assemblies on irrigation or fire lines. A sewer backwater valve is in the drain. Read the notice. If it names a lawn or a fire line, use the backflow page.

Can I maintain it myself?

You can be the person who knows it exists and who calls when it sticks. This page will not give installation or service steps. A stuck valve can either let sewage in or stop your own drains. Ask the installer where it sits and how you will know it failed.

Plumber repairing sink in bathroom with tool — **Fixture maintenance:** Aurora Water and regional building departments maintain clear standards for residential water and sewer lines.