Safety & Requirements

Safety & Requirements

At Onsite Tanks, safety is our first priority.

Government Requirements

BASIX for residents in NSW

The Building Sustainability Index (BASIX) states that a new home in NSW must include an alternative water supply to mains water. A rainwater tank is one way to satisfy this requirement. BASIX also covers renovating old homes, ie properties that plan to install a swimming pool must use a tank to supply water to the pool. These standards vary according to region. Visit for more details.

After your tank is completed

Owners’ Responsibilities

It is the owners’ responsibility to:

  • Ensure all gutters, roof catchment areas are clean and free from leaves and debris
  • Screens, filters or netting should be fitted to all down pipes
  • All access points in the tank should be closed/sealed immediately if not in use
  • It is recommended that your tank is examined every 1-2 years and if dirt or sediment is present the use of a vacuum pumper truck can be used to empty and clean out tank
  • Installation of pump and electrical connections should only be carried out by licensed trades people
  • Removal of the manhole cover and access to tank must not be carried out by anyone other than by the owners authorized persons.

It is recommended that you fill the tank to a minimum level of 20% capacity; as soon as possible once tank has been installed. This is to aid curing of the concrete and most of all, avoid floatation of the tank.

We recommend a flush out of the tank prior to the first fill/use.

Should Council require, we can supply you with an engineers detailed drawing and specifications of the installed tank. An engineers certificate will incur an additional fee and must be requested and approved prior to tank commencement and construction. Each design complies with the relevant sections of the following Australian Standards Codes

  • AS 3600 – Concrete Structures
  • AS 3735 – Concrete Structures for Retaining Liquids

Information for Civil Works and Finishing Contractors

  • When backfilling the tank, ensure that all filling materials are approximately 100mm or less (any large or sharp rocks can damage fresh concrete)
  • During backfilling and compaction any damage caused by machinery and large rock/debris is the responsibility of the owner or prime contractor.
  • Divert any storm water runoff from entering tank site/hole.
  • If possible construct sub soil drainage for any in ground tanks.