How To Dissolve Urine Crystals In Urinals

Most urinal crystals are struvite + calcium phosphate due to urease-producing bacteria.

Crystals form when urine sits. In low-traffic restrooms, manually flush each urinal daily, even if unused. For automatic flush valves, ensure the sensor is working.

The Problem: You walk by the restroom, and that sharp, unmistakable ammonia smell hits you. Or worse, the urinal drains slower than a sloth on vacation. how to dissolve urine crystals in urinals

That’s not just "dirt." That is struvite (urine scale)—a rock-hard crystal made of calcium, magnesium, and phosphates. Unlike toilet bowl rings, these crystals solidify into concrete-like deposits inside the trap and drainpipe.

The Bad News: Bleach and regular soap don’t touch it. In fact, bleach makes it worse by driving ammonia gas into the air. Most urinal crystals are struvite + calcium phosphate

The Good News: You can dissolve them. Here is the safe, effective chemistry to get your urinals flowing like new again.

Attempt the above methods first, but call a plumber if: Crystals form when urine sits

Urine crystals (commonly uric scale) are mineral and organic deposits formed when urine salts and uric acid precipitate and bind to surfaces. They appear as hard, yellow-white or brown crusts around drains, weep holes, and trap areas and can cause odors, slow drainage, and blockages.

When urine sits in a P-trap, the urea breaks down into ammonia and carbon dioxide. This raises the pH, causing minerals to precipitate out of the liquid and weld themselves to the porcelain and PVC. Over months, this creates a plug that looks like a gray, crunchy stalagmite.