Why My Cat’s Water Fountain Suddenly Got Loud (And What I Found Inside)

I didn’t think much of it at first.

After about 2–3 months, my cat’s water fountain started making this low buzzing noise. Not super loud, but enough to be annoying at night.

At first I thought it was just getting old.

But when I finally opened the pump to check, I was honestly a bit shocked.

There was this slimy brown buildup inside. It wasn’t just dirt — it looked like something growing in there.

What’s actually happening

Over time, things like:

cat saliva
tiny food particles
dust and hair

get pulled into the pump.

If you don’t clean it regularly, it builds up and starts affecting how the pump runs.

That’s when:

the noise starts
water flow weakens
the pump struggles
The part most people don’t realize

That slimy layer inside?

It’s often biofilm — basically bacteria buildup that thrives in wet environments.

What worked for me

I started doing two simple things:

Clean the pump more regularly
Let it fully dry (sometimes even in sunlight)

But the biggest improvement came when I got a second pump.

Now I just rotate them:

one in use
one cleaned and drying

No more noise. Problem solved.