Washing Machine Standpipe

graemew said:

There is a backflow preventer that protects the basement toilet and shower, but I know that they weren't original. The floor drain, washer drain and upstairs fixtures weren't protected by this backflow preventer.

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It's good that your pipes are open now. You may want to consider getting that clay tile replaced with PVC or get that line opened every year or so. I am a little surprised that the bladder did not dislodge the lint. I think you want to start using a lint trap on the output of your washing machine hose.

A sewer check valve (Backwater Valve) is intended to prevent the city sewer from backing up into the basement, but the common normally closed ones, with hanging swinging gate, are not very effective. Material lodges in place, and holds the flapper open partially.

The normally open ones, that close due to a float raising the gate in the face of rising water, are usually much more reliable. You need to recognize to stop using water if the valve closes.

Reach4, the lint trap sounds like a good idea. Thanks!

The build up of lint was around the corner of the P-trap so I wasn't able to blast the lint directly. There was always some path through there, so the water must have just flown past.