I have two bathrooms, both with sinks. The drain pipes repeatedly clog with a mysterious white slimy substance. All that is ever put down the drains is water and liquid hand soap. What could this slimy white substance be?

Sludge in bathroom drains is a combination of soaps, shampoos, conditioners, tooth paste, mouth rinse as well as body oils and hair. You can minimize accumulation of such sludge by using more (hot) water to flush these products down the drain or experiment with different brand of body hygiene products .

Hope that helps

Milo

I am with Milo on this. Periodically pour a tea kettle of near boiling water down each drain. You could also do a tables spoon of baking soda and one of salt followed by a cup of vinegar to really rinse out the drain.