What can go wrong with a water tank?
Most landed houses in the Klang Valley store water in a roof tank or a tank on a stand. Scheduled maintenance and burst mains cause water cuts, so a tank is useful storage. But tanks need attention. Our home plumbing guide for Kuala Lumpur covers what happens to tanks, pumps and heaters during a cut.
- Sediment builds up with each refill, especially after an Air Selangor water cut.
- Algae grows where light gets in through a poor lid or a translucent tank.
- The float valve or ball valve sticks or wears, so the tank overflows or stops filling.
- Fittings leak at the inlet, tank outlet valve or overflow pipe.
- Steel tanks corrode, and plastic tanks crack with age and sun.
What will you notice?
| Symptom | Likely cause | Guide |
|---|---|---|
| Overflow pipe dripping | Float valve not shutting off | Water tank overflowing |
| Stain on the ceiling below the tank | Leaking tank or fitting | Roof leak or pipe leak? |
| Dirty, cloudy or smelly tap water | Sediment or algae | Brown or rusty tap water |
| Tank not filling | Float valve stuck, blocked inlet, low supply | See below |
| Rust or cracks | Ageing tank | Repair or replace? |
How often should a tank be cleaned?
Clean it when you see the signs: sediment on the bottom, slime on the walls, dirty or smelly water at tank-fed taps. Put a tank check on your yearly home plumbing checklist, and look again after long or repeated water cuts.
What can you safely check yourself?
Only if you can reach the tank safely, with boards to stand on in the roof space, good light and a cool time of day:
- Look at the water for sediment, algae or anything floating.
- Check the lid fits.
- Look for rust, cracks and damp around the fittings and below the tank.
- Lift the float arm gently. Does the water stop?
- Check the overflow pipe outside is dry.
Never stand on ceiling boards.
Tanks and water cuts
A full tank can carry a household through a short water cut. Before a planned cut, check the tank is full. During it, switch off the booster pump if the tank may run dry. After it, expect some sediment. Our guide to a water cut in the Klang Valley covers each step.
Choosing a tank
Stainless steel and polyethylene tanks both work well when well made and well installed. Our comparison of stainless steel and polyethylene water tanks covers durability, weight, algae and sizing.
Condo unit
Shared tanks belong to the building. If tap water is dirty across several units, ask building management when the tanks were last cleaned.
When should you call a plumber?
Call a plumber if the overflow keeps running, the tank leaks, the water stays dirty after cleaning, you see corrosion or cracks, or you cannot reach the tank safely. The partner’s published tank cleaning and replacement prices, with source and date, are listed further down this page.
