Most tanks require an overflow to comply to water regulations
part of the regulations are to prevent the inlet getting submerged and thus increases the change of contaminating the mains supply
therefore to help reduce this tanks and vessels should be fitting with an overflow so that if the water level becomes higher that normal say due to the inlet not shutting off the water has some where to go via the overflow to prevent the level submerging the inlet and potentially filling beyond the top of a tank and spilling over and into the surrounding area
in conclusion any tank not designed as a pressure vesssel should have an overflow and vent to equalise any pressure from water coming into the tank and the vacuum from the water going out,
for water tanks the overflows and vents should also be screened with a mesh to prevent ingress of debris and insects rodents and other vermin
see our range of overflow fitting’s here
