Every three months: Check your gutters are clean to avoid faecal matter being washed into your water tank. Gutter mesh can help limit what ends up in your water tank.
Every three months: Check the mosquito mesh on your water tank is in good repair to limit disease-carrying insects and other vermin getting into your water tank.
Every six months: Check the quality of the water in your water tank, looking at the colour, smell and level of sediment.
Every six months: Check that the pumps and pipes on your water tank are all intact and functioning.
Every two to three years: De-sludge your water tank. It’s recommended you use a qualified contractor to remove the sediment that builds up in your water tank.
Source: CSIRO