SewerOwner

Backwater valve work

Installing, replacing, or servicing a device intended to resist reverse flow.

What this page cannot establish

  • SewerOwner cannot establish whether backwater valve work is appropriate for your property
  • this approach cannot establish that a device will prevent any particular event
  • this approach cannot establish that a device is required or permitted in your jurisdiction
  • this approach cannot establish that a device removes the need for other work

What it attempts to do

Install or maintain a device positioned to resist flow returning toward the building from the downstream system.

When contractors may discuss it

These are circumstances in which the approach comes up, not a checklist that makes it correct. There is no situation in which one method is universally right.

  • when reverse flow from the downstream system is part of the discussion
  • where a local process addresses such devices
  • when an existing device has not been serviced or inspected

What has to be known before applicability can be judged

If a proposal for this work is priced without these, it is priced against assumptions. That is not necessarily wrong — but the assumptions should be written down.

  • what the operating authority says about such devices locally
  • whether one is already installed, and where
  • what the device would and would not sit downstream of
  • what maintenance access it would need

Access and site considerations

  • position determines what the device sits downstream of
  • requires ongoing access for inspection and maintenance
  • installation may require excavation and a permit

What to clarify in a proposal for this work

These are the details that most often differ between two proposals for what sounds like the same job.

  • the proposed position and what it protects
  • what it does not protect
  • the maintenance the device requires and who performs it
  • whether a permit and inspection apply
  • what the warranty covers

What to keep afterwards

  • the recorded position of the device
  • the permit and inspection record
  • maintenance records over time

Alternatives worth asking about

Asking why one approach is proposed rather than another is a reasonable question, and the answer tells you what the contractor believes about your line.

Traditional excavation

Digging along the line to expose and replace pipe directly.

Expose the line so that pipe can be removed and replaced, and so that what is uncovered can be observed directly.

Cannot establish: the condition of any section outside the excavation; that no further conditions exist elsewhere; that the new installation will perform for any stated period.

Cleanout installation or replacement

Adding or replacing an access point on the line.

Create a usable access point so that future inspection and cleaning can be performed from a known position.

Cannot establish: the condition of the line; that the access point reaches the full line.

What would change the answer

  • what the operating authority says about such devices locally
  • whether one is already installed, and where
  • what the device would and would not sit downstream of
  • what maintenance access it would need

What to do next

A valve protects only what is upstream of it, so the position is the whole question.

Ask what sits upstream of the proposed position

If your situation is different

Related, and why