Wet Areas

Managing water overflow and splashing

Wet areas should be designed to minimise damage from water overflow and splashing.

On this page:

• preventing overflow damage
• preventing damage from splashing

Acceptable Solution E3/AS1 provides a means of compliance for three aspects of wet area design. Acceptable Solution E3/AS2 Internal Wet-area Membrane Systems provides a means of compliance for Building Code clauses E3.3.2–E3.3.6.

Preventing overflow damage

Overflow or flooding is generally the result of user error such as leaving a tap running, a blocked outlet, a leaking pipe or joint or a faulty appliance. Flooding is often not considered during the design of a wet area but, if uncontained, water can damage adjacent rooms or occupancies. Flooding can be contained by:

• a floor waste to drain water safely away
• continuous, impervious floor coverings
• coved or sealed floor-wall junctions.

Floor wastes should be installed in all:

• upper floor wet areas
• wet areas with a high risk of flooding, e.g. facilities for children or elderly

It is a statutory requirement to provide floor wastes or drains in multi-unit dwellings.

Other measures to minimise the risk of flooding include:

• ensuring that the floor falls to the floor waste (this is a mandatory requirement within the shower area)
• incorporating a water barrier at doorways to wet areas
• specifying fixtures with inbuilt overflows
• ensuring subtrades know where pipes are located (to reduce the likelihood of a tradesperson inadvertently damaging a pipe during construction)
• specifying fixtures for hand washing only with spray taps and no plugs
• specifying taps with a timer or automatic turn-off for some situations
• fitting pressure reducing valves or flow restrictors in facilities such as accommodation for the elderly
• specifying hose burst valves for high water use appliances such as washing machines and dishwashers.

Preventing damage from splashing

E3/AS1 requires impervious and easily cleaned finishes to floors and walls subject to water splash, within showers and around urinals. This will prevent damage from splashing.

^{Updated: 12 November 2020}