Why is there white stuff in my drain?
If you've lifted a floor grate, looked into a pit or had a plumber show you camera footage, you may have seen white, grey or creamy build-up coating the inside of the pipe. It's one of the most common causes of slow and blocked drains, and what it is depends on where it's found. Here's what the white stuff usually is, why it builds up, and how it's cleared.
What it usually is
Fat and grease (kitchen)
Fat, oil and grease poured down the sink cool and set on the pipe walls. Over time they react with detergents and turn into a hard, waxy, white or cream layer that narrows the pipe.
Soap scum (bathroom and laundry)
Soap and washing powder combine with minerals in the water and leave a white, chalky film, often with hair and lint caught in it.
Mineral scale
Hard white deposits from minerals in the water, more common around hot water discharge points and in older pipes.
Washing powder residue
Too much powder, or powder that doesn't fully dissolve in cold washes, can clump in laundry drains.
Why it matters
A pipe coated in fat or soap gets narrower every month. Water drains slower, food and hair catch more easily, and one day it blocks. Kitchen fat build-up is the most common reason the kitchen sink blocks while the rest of the house drains fine. See gurgling drains.
How to stop it building up
- Never pour fat or oil down the sink. Let it cool, wipe it out with paper towel and put it in the bin.
- Scrape plates into the bin before rinsing.
- Use a sink strainer in the kitchen and a hair catcher in the shower.
- Don't overdo washing powder, and consider liquid for cold washes.
- Avoid chemical drain cleaners. They don't remove set fat properly and can damage pipes.
How we clear it
A high-pressure jetter cuts through fat and soap build-up and flushes it away, restoring the full width of the pipe. We can check the result with a camera so you can see the pipe is clean. You get a fixed price before any work starts. See drain jetting.
In southern Eastern Suburbs homes
Older homes in Matraville, Maroubra and Kingsford often have kitchen lines that have collected decades of fat, especially where the pipe runs a long way to the sewer under a timber floor. When we jet them, the white build-up comes out in chunks.
Why locals call us
- Local to Matraville and the southern Eastern Suburbs
- Free on-site quotes, with a fixed price before any work starts
- Lifetime labour warranty on our workmanship
- 100+ five-star Google reviews
- Licensed plumbers and gasfitters (Lic. 398171C)
Common questions
What is the white stuff in my kitchen drain?
Usually fat and grease that has set on the pipe walls and reacted with detergent, forming a hard, waxy layer.
What is the white build-up in my shower drain?
Usually soap scum mixed with minerals, often with hair caught in it.
Can I dissolve fat in my drain with boiling water?
Hot water can help a little with fresh grease, but it won't remove set fat. It's best cleared with a jetter.
How do I stop fat building up in my drains?
Don't pour fat or oil down the sink, scrape plates into the bin and use a sink strainer.
Related help: drain jetting, blocked sinks, gurgling drains, blocked drains and drain flies. Local pages: blocked drains Matraville, blocked drains Maroubra, blocked drains Kingsford and blocked drains Botany.