What Is That Pink Slime in Your Toilet or Sink?

If you’ve noticed a pinkish film or ring forming in your toilet bowl, shower, or pet’s water dish, you're not alone. This unsightly substance is commonly known as pink slime, and it’s caused by a type of airborne bacteria called Serratia marcescens. Despite its name, it's not a form of mold or a sign of untreated water—it’s a natural environmental bacterium that thrives in damp, low-light environments.

Think of it like dandelions in your yard. Even with healthy soil and good lawn care, dandelions can float in from anywhere and take root. Similarly, pink slime spores can enter your home through the air, landing in moist areas where they begin to grow. A water filter system—no matter how advanced—won’t stop this airborne issue, because it’s not coming from your water supply.

Where Does Pink Slime Appear?

You'll typically see it in:

• Toilet bowls (especially under the rim)
• Shower corners and drains
• Pet water bowls
• Standing water in sink basins or containers

How Can I Prevent or Remove It?

• Clean affected surfaces regularly with vinegar or a diluted bleach solution
• Ventilate bathrooms and laundry rooms to reduce humidity
• Dry off wet surfaces with a towel or squeegee
• Change pet water frequently and wash dishes with hot water

While pink slime doesn’t usually pose a serious health risk to healthy individuals, it's definitely annoying—and gross. If you’re dealing with other water quality issues like iron, hardness, or odor, we recommend checking out the ICS-STP Whole House System, which helps solve common household water complaints at the source.

Not Sure What You Need?

Take our quick Filter Finder Quiz or schedule a free consultation with a Cascadian pro.

← Back to Water Quality Problems