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Saturday, February 10, 2007 - Page updated at 12:00 AM

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Ask the Expert

Keep your sewer line clean and clear

Special to The Seattle Times

Q: My sewer is backing up into my floor drain. I had roots cleared from the sewer line a few months back, but they seem to keep coming back. Any hints?

A: For those not familiar with this issue, the "side sewer" from the house to the main municipal sewer line in the street is the responsibility of the owner of the property. Many homeowners need to have their lines snaked or derooted by sewer cleaning contractors or plumbers once a year or so. Chemical treatments can help keep the lines free of roots between calls.

Copper sulfate is widely available and known to be effective at ridding a line of roots, but it can damage or kill the plant. Copper sulfate also is toxic to fish. There are restrictions on its use during certain times of the year (for fear of it entering bodies of water directly during flood conditions).

There are a couple of alternatives that contain dichlobenil (Casoron) and enzymes. RootX is available only to professionals, but Foaming Root Killer is widely available to consumers.

As roots are the biggest problems for side sewers, it is important to know where your line is, to plan landscaping accordingly and to remove offending greenery if it chronically is causing issues. Seattle homeowners can see a graphic representation of their side sewer at

Of course, roots aren't the only cause of side-sewer difficulties — just the most frequent.

Rick Delamare sees root blockages every day, but collapsed and crushed pipes, dips in the line, broken pipes and disconnections are also fairly routine. He's the owner of a local Hydro-Physics franchise, one of the companies that uses a submersible camera in sewer inspections.

Honestly, I thought he would see quite a few GI Joes and Barbies, but apparently not. The thing that surprised me was how often Delamare sees phone lines, gas lines and electrical ground rods driven through the middle of a sewer pipe. Boring machines don't care if they go through the middle of a pipe, and an electrician's sledge hammer cannot differentiate between a rock and the sidewall of a sewer pipe.

Grease may also build up and block a sewer line (not especially common in homes). Coring or jetting tools can clear this blockage.

Sewer lines also may have partial blockages that are going undetected. The pipe may fill up behind the blockage point and slowly bleed down during the course of a routine day. But when guests come over and the shower usage triples, then a problem is discovered.


Delamare says a "glupping" sound may be the indicator of a partially blocked sewer. A professional can clear the line.

Q: Can you give me a quick checklist of things to look for concerning leaks in the crawl space or basement?

A: This is a very complex issue with many variables, but here is a condensed version of options for fixing the problem:

1. Move the downspout water away from the foundation.

2. Grade the soil near the foundation to drain water runoff away from the house.

3. Seal any obviously leaking cracks or foundation holes with hydraulic patching cement.

4. Install an interior and/or exterior drainage system with drainage rock and perforated pipe to carry water away by gravity. This gives the water a path of "least resistance" away from where you don't want it.

5. Add a sump pump when gravity can't do its job.

Darrell Hay is a local home inspector and manages several rental properties. Send home-maintenance questions to Sorry, no personal replies.

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