Plumbing is used every day yet rarely seen until something goes wrong: a weak upstairs shower, a pump that cycles with nobody using water, a bill that keeps rising, or damp patches on bathroom walls. Most problems are easy to fix once you understand how the system works. This guide suits people building or renovating and buyers of second-hand homes checking the water system.
Most Thai homes don't get enough mains pressure for upper floors or several outlets at once, so they need a pump. The correct layout lets mains water fill a storage tank, with the pump drawing from the tank into the house. Connecting a pump directly to the mains is bad practice: it disrupts pressure in the public network, affects neighbours and can draw contaminants in, which is why waterworks authorities prohibit it. A tank also provides reserve water when the mains supply stops.
| Type | Pros | Watch for |
|---|---|---|
| Above-ground (stainless/plastic) | Easy to install, inspect and clean | Takes space; place in shade to limit algae and heat |
| Underground | Saves space, hidden from view | Leaks are hard to detect; groundwater ingress if poorly repaired |
Size the tank for at least a day of household use, clean it periodically and check the float valve shuts off properly without overflowing.
Two types dominate homes. Pressure-tank automatic pumps store pressure in a small vessel and switch on and off by pressure; they're inexpensive, though pressure may fluctuate slightly in use. Constant-pressure pumps modulate to keep pressure steady, ideal for showers and water heaters, quieter but pricier.
Size by how many outlets may run at once — bathrooms, washing machine, kitchen tap — and the house height; a three-storey house needs more head than a bungalow. Oversized pumps waste power and create high pressure that makes joints leak; undersized ones give weak flow when several taps open. Have a plumber size it, and install it under cover, ventilated and earthed.
PVC is the standard for cold water — cheap and easy to install, but unsuitable for hot water. PPR pipe, joined by heat fusion, handles hot and cold with strong joints, suiting homes with central water heaters. Some older homes still have galvanised steel pipes that rust internally over time, reducing flow and discolouring water; consider replacing them when renovating.
Kitchen wastewater should pass through a grease trap before the drain, or fat builds up, blocking pipes and causing odours; skim it regularly. Bathroom waste goes to a septic tank that needs periodic desludging; avoid frequent harsh chemicals in toilets, which kill the digesting bacteria. Bathroom smells or slow-flushing toilets often signal a full tank or a vent-pipe problem.
It depends on quality and care. Shelter, ventilation and not letting leaks keep it running constantly extend its life considerably. Unusual noise or frequent cycling warrants a check.
The building's main supply is the juristic person's responsibility; pipes and fittings inside the unit are the owner's. Leaks from your unit into the one below are your responsibility.
It depends on local water quality and use. A sediment filter at the inlet protects appliances such as water heaters; choose drinking-water filters to suit your household.
Good plumbing starts with the right layout — mains to tank, pump from tank — a correctly sized pump, pipes suited to hot and cold water, maintained wastewater systems and regular meter leak checks. More home-care and renovation guides on the MyProperty blog.
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