Sink Drains Slowly: 5 Causes and What Actually Fixes Them
By JW Moore Plumbing • Updated 2026-09-17
A slow drain is a clog in progress. Here's how to tell what's building up and when chemical cleaners make it worse.
Hair and soap scum (bathroom)
The most common bathroom culprit. A drain snake or zip tool pulls most of it out; a plumber's cable machine clears the rest.
Grease and food (kitchen)
Grease cools and coats the pipe, then catches rice, coffee grounds and peels. Hydro jetting scours the pipe walls clean rather than punching a hole through the sludge.
A blocked vent
If drains gurgle and drain slowly everywhere, the roof vent may be blocked by leaves or a bird's nest, creating a vacuum.
Why chemical drain cleaners backfire
Caustic cleaners heat and soften PVC, corrode older metal pipes and rarely remove the full clog. They also make the plumber's job dangerous.
Sewer line problems
If multiple drains are slow, especially the lowest ones, the issue is likely the main sewer line — roots, a belly or a break. A camera inspection tells you for sure.
Need a Plumber Now?
JW Moore Plumbing offers drain cleaning & clogged drains across Hawaii — 24/7, same day, flat-rate pricing. Call (888) 480-9811 or book online.