Kwinana facts that change the job
Family houses
Across the City of Kwinana's area, 93.0% of occupied homes were separate houses at the 2021 Census. 53.6% were owned with a mortgage and 27.6% rented.
No more basic septic tanks
Rural and industrial areas often need on-site effluent systems, but the City no longer approves conventional primary treatment septic systems anywhere.
Nutrient-sensitive areas
Nitrogen-sensitive areas include Wellard west of the Freeway, Kwinana Beach, Hope Valley and Mandogalup; phosphorus-sensitive ones include Wandi, Casuarina and Anketell. Systems there must be nutrient-retentive.
High water tables in rural zones
In Rural and Special Rural zones, the City wants floor levels at least 2 metres above the water table, which can also affect septic systems and how high a house pad must be.
Buying a property that had a septic tank
Once a property is on mains sewer, the City requires the septic system to be decommissioned when the property is sold, with new owners given 60 days, or within 60 days of a change of use. The same applies before new building work that would sit too close to it.
A licensed liquid waste contractor pumps out the tanks, soakwells and leach drains, which are then removed, or their lids and bases broken and filled with clean sand. Not sure if a property is connected? Water Corporation can confirm it. A new system can't be used until a City officer issues a Permit to Use. See our septic systems page.
Stormwater and rainwater tanks
Rain and pool water must stay on your site and not cause damage or nuisance next door. The City wants downpipes no more than 12 metres apart feeding soakwells, each set back at least its own width from buildings and boundaries, built to the Building Code and AS/NZS 3500.3.
A small steel or fibreglass rainwater tank needs no building permit if it's 1.8m tall or less, holds under 5,000 litres, sits in the back yard out of view of the street and stands no higher than 300mm. More on rainwater tanks.
Homes on sewer
For sewered homes, Water Corporation's line applies: the owner clears blockages in the property's own connection, up to the junction with its main, and a blockage in the main is Water Corporation's. See blocked drains in Perth or, after hours, an emergency plumber in Perth.
What we would do
Buying a rural lot in Kwinana? Before you sign, ask whether it's on sewer, what on-site system it has and whether it sits in a nutrient-sensitive area. A plumber who specialises in septic and aerobic systems can then tell you whether the existing system meets the City's rules or will need replacing with an approved type.