Backflow and backwater valves
When the drains back up in a heavy rain
Two different valves do two different jobs. Most people need to know which one they are asking about.
The sewer side: a backwater valve
In a heavy rain or a very high tide, the public sewer can fill past its pipes and push back toward the house. Without a valve, the water looks for the lowest drain: a floor drain, a shower or a toilet on the ground floor. A backwater valve sits in the line and closes when the flow reverses.
The drinking-water side: a backflow preventer
An irrigation system or a hose left in a bucket can let dirty water slip backward into your drinking-water line. A backflow preventer stops that. Many water authorities require one on irrigation, and some require a yearly test; ask yours.
What a visit looks like
We find where the line leaves the house, say which valve fits and where it would go, and write the price before we cut anything. If a slab or a driveway is in the way, we say so then.
Signs
Signs a valve would have helped
Water in the lowest drain
Water or sewage comes up a floor drain or shower in the rain.
Gurgling in a heavy rain
Drains gurgle when the street is running full.
A buried irrigation line
The system has no preventer, or no one has tested the one it has.
A house below the street
A garage or ground floor sits lower than the road or the manhole.
The visit
What a backflow visit covers
- 01
Step 1: We find the line
Where the sewer and the irrigation lines leave the house, and what is in the way.
- 02
Step 2: We say which valve
A backwater valve, a preventer, or both, and where each would sit.
- 03
Step 3: We write the price
Before any cutting, with permit fees on their own line.
- 04
Step 4: We show you the lid
Where the access lid is, how it opens and how to keep it clear.
Questions
About valves and permits
Does a backflow preventer do the same job as a backwater valve?
No. A backflow preventer protects your drinking water from irrigation and hose lines. A backwater valve sits on the sewer line and stops sewage coming back up your drains. The backflow page explains both.
Do you pull permits?
When the job needs one, yes. Permit fees appear on their own line in the written price. Moving a water heater or a main line usually needs a permit; ask the building department in your town.
Will I get a price before you start?
Yes, in writing, by text or on paper, before any work starts. If we open a wall and find more, we stop and send a revised price.
Ask about your line
Tell us where the water comes up
A photo of the lowest drain and the street side of the house is enough to start.