Tampines has a large stock of older HDB blocks, and ageing flats bring the plumbing faults you would expect: dripping taps, weak flush cisterns, choked toilets and sinks, and leaks that show up as stains on the ceiling below.
A leak in one flat is often a problem for two households, which is why people search the symptom rather than the trade. Under PUB rules, regulated water service and sanitary plumbing works must be done by a PUB licensed plumber.
Larger bathroom works can also need HDB approval, so a good page tells owners to check before any hacking starts. Water heater replacement is a steady planned job for households refreshing a bathroom.