Clogged Backwash Drain Line


New member
Aug 16, 2007
Hi. The pipe that drains water and DE from my filter during backwashing is clogged (the drain line goes directly to the sewer). I applied pressure to the line via garden hose and a pool maintenance man applied pressurized air. In both cases the clog held (the pool guy said he's never heard of a backwash line clogging). I'd like to know if anyone has heard of or experienced this problem and, if so, what the solution was. Thanks in advance for your advice.


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
Hi, Kevin,

Welcome to TFP. That's pretty difficult to clog the backwash line, Assuming it's pvc pipe, nothing can get in to clog it unless it's broken somewhere. My only other thought is that the drain end may be clogged from something backing up in the sewer.

Never heard of it and have no clue. Since you can get air to it, I assume you can snake it.


Well-known member
Apr 2, 2007
Some animal may have crawled in from the sewer end and died in there, try drano, it may be enough to break a bit of it down around the perimeter and allow it to flush out.

The Mermaid Queen

TFP Expert
LifeTime Supporter
Mar 28, 2007
Northern KY
What about using what we call a 'water weenie'? Somebody has posted photos and the real name before... it is a rubber hose-end attachment that you put into the unclogged end of pipe. Turn on the water, and the pressure builds up in it, and it swells up to close off the pipe. Then when the pressure gets high, it blasts out the clog.
You can get them at HD or other hardware store.

In re-reading this description, well, :oops: