Stormwater infiltration occurs when rainwater enters the sewerage system on a property. In compliant plumbing, runoff from landscaped areas and rainwater from roofs and gutters is not directed into the property’s sewerage system. Rainwater should be exiting the property via the stormwater drainage system.
How Altogether identifies properties impacted by stormwater inflitration
Altogether identifies “stormwater infiltration” properties as those:
- that produce over 1500 litres of wastewater per day during wet weather; and
- whose wastewater production during wet weather is 150% or more of their wastewater production during dry weather.
For comparison, a typical Altogether customer household produces an average of 400 litres of wastewater per day.
Where stormwater infiltration is not present, wastewater production doesn’t change significantly during wet weather.
Causes of stormwater inflitration
Rainfall can enter the on-lot collection tanks in a variety of ways:
- Via the Overflow Relief Gully. Please see: Keeping Stormwater out of your Gully
- Incorrect landscaping that drains water toward the sewerage collection tank instead of away from it. Please see Altogethers Landscaping Guide.
- Existing damage to sewerage pipes or collection tank during construction of the house. Please see Altogethers Building Guide.
- Non-compliant connection of stormwater drainage into sewerage system. Please see Altogethers Building Guide.
- For properties with a pool, pool pumps must not be discharging into sewerage system. Please see Swimming pools and spas.
Altogether recommends that you arrange for a licence plumber to thoroughly inspect your wastewater system for damage and non-compliance, and that any such defects be rectified without delay.
Why Altogether charges customers for stormwater inflitration
Each litre of wastewater a customer produces is treated at a local Altogether water centre. The more stormwater that enters the sewerage system, the more wastewater needs to be treated, and the more it costs to operate this infrastructure.
When Altogether charges customers for stormwater inflitration
Once stormwater infiltration is identified at a property, Altogether provides the account holder at least 90 days to have a plumber inspect and repair any damage and non-compliance.
If after at least 90 days, stormwater infiltration is present, a monthly stormwater infiltration charge will be applied to the account. For current charges, please see the applicable Price Fact Sheet here: Community fees and charges - water.
How to stop stormwater infiltration
Your plumber may be able to identify stormwater infiltration by:
- Checking the area around the on-lot collection tank to make sure water isn’t draining into the tank and the tank meets the requirements in Altogethers Landscaping Guide.
- There should be no wells, fill, moats, or trees next to the wastewater collection tank
- As per Altogethers Landscaping Guide, there should be a minimum clearance between the outer rim of the wastewater collection tank and finished soil levels. If not, your wastewater collection tank may require a wastewater collection tank riser.
- Checking all overflow relief gullies, ensuring they’re sufficiently above the surrounding ground level. Please see: Keeping Stormwater out of your Gully.
- Ensure all downpipes aren’t connected into sewerage piping.
- For customers with a pool without a buffer tank or restriction, consider installing a buffer tank to slow down the release of stormwater into their sewerage piping. Refer to our pool and spa guidelines here: Swimming pools and spas.
These are just some examples of where stormwater may infiltrate the wastewater system. We recommend that you arrange for a licence plumber to thoroughly inspect your wastewater system for damage and non-compliance. The following guides are designed to assist you and your plumber:
I've had a licenced plumber fix defects
Once defects causing stormwater infiltration are resolved, upon request, Altogether will inspect the rectification works completed by your plumber. To request an inspection, please complete the following form with the enquiry type: Stormwater infiltration: Contact us.
If the rectification works completed by your plumber comply with the following guides and all relevant laws, codes of practice and Australian standards, you will not be charged for the inspection.
If rectification works fail to comply with the above, an infiltration inspection charge will apply. For current charges, please see the applicable Price Fact Sheet here: Community fees and charges - water.
I'm being charged a stormwater inflitration charge, but I've had a plumber rectify the defects
Please request and inspection by completing the following form with the enquiry type: Stormwater infiltration Contact us.
If the rectification works completed by your plumber comply with the following guides and all relevant laws, codes of practice and Australian standards, you will not be charged for the inspection and Altogether will stop charging the stormwater infiltration charge.
If rectification works fail to comply with the above, the stormwater infiltration charge will continue and a one-off infiltration inspection charge will be placed on the account. For current charges, please see the applicable Price Fact Sheet here: Community fees and charges - water.