10 Check all drain pipes for satisfactory water/gas
tightness and adequate water seals and traps to prevent backflow of
sewage gases into the toilet compartments. Check that all sanitary
fittings are securely fastened to prevent relative movement at pipe
joints. Toilet bowls incorporate a water trap and are often fitted
with vacuum breaking arrangements at the back of the trap such as
individual air pipes or patented backflow prevention valves. Such
items should be checked for satisfactory condition and operation.
There should be an adequate supply of flushing water to clear the
toilet blow and to replenish the water seal.