Plumbing Home Inspections
Water supply and water heating
Plumbing inspections by home inspectors cover both the supply of water to a home and the removal of waste water and sewerage.
The primary function of the water supply plumbing systems within a building is to bring an adequate and potable supply of hot and cold water to the users of the building. The home inspector must understand all elements of these systems so that the inspector may recognize inadequacies of the structure’s plumbing and also any violations of the regulations.
The home inspector must be thoroughly familiar with the following:
- Supply pipes – types, regulations and common problems
- The issue of water pressure and how the cold and hot water supply system should be balanced.
- Taps and mixers.
Hot water heaters
The home inspector must be knowledgeable regarding compliant installations of all types of hot water heaters including: Electric pressure geysers; gravity fed hot water heaters, solar geysers, heat pumps and tankless instant hot water heaters.
The most common hot water heater used in South Africa is the electric pressure geyser which is mostly installed within the roof cavity. HouseCheck requires its inspectors to check that:
- Geyser support is in accordance with regulations
- The geyser has its own circuit breaker on the DB board
- There is an electrical isolator switch within easy reach of the geyser
- There is no exposed wiring. Geyser cover plate is in place
- The cold water supply to the geyser has a stop cock
- The geyser has been fitted with a sloping drip tray with overflow leading to the exterior
- The cold water pressure balancing valve is fitted with a 12mm overflow (plastic or metal) leading to the exterior (not discharging in the drip tray)
- The two vacuum breaker pipes are at least 40mm high and positioned over the drip tray
- The temperature and pressure (T&P) release valve on the hot water exit pipe is fitted with a 20mm metal overflow pipe discharging safely to the exterior
- The pressure rating of the T&P valve matches the pressure rating of the geyser – kPa.
Drains and waste removal
To inspect and report on drain systems the home inspector needs to know the following important principles:
- Drain systems are powered by gravity (only very occasionally) by pumps. Underground drain lines are therefore constructed with a gradual fall from the home to the municipal sewer or on-site sewerage system (conservancy tank, septic tank and soak-away).
- Unpleasant smells and vermin (cockroaches and rats) from the drains are kept out of buildings by means of water seals on the subsidiary waste lines. This means that the waste pipes linking toilets, sinks, basins, baths, showers and bidets are all fitted with a water seal “trap”.
- If the air pressure inside the drain drops lower than the outside atmospheric pressure, then the resultant vacuum within the drain will suck out the water seal into the drain – thereby allowing unpleasant smells to penetrate from the drain inside the building.
Drain lines mostly become blocked as a result of either:
- Root penetration of the drain.
- Poor drain design – if the bends in the drain line are too acute, or if the gradual fall in the drain line is insufficient to allow the waste to flow at an acceptable pace and self-cleanse.
For this reason, National Building Regulations prescribe that there must be access to the underground drain lines on bends in the drain line in order to permit “rodding” of the blocked line in order to clear the blockage. In older drain installations cast iron inspection manholes are installed over every bend or junction. In more modern installations plastic rodding eyes are installed level with the ground.