Septic Servicing FAQ — Central Coast

As a general guide, a septic tank is often pumped out every 3-5 years, and sooner for a bigger household or a smaller tank. On the Central Coast, every on-site system has to be registered with Council and hold an approval to operate, so check that approval for any servicing conditions that apply to yours. A pump-out is priced on the size of the tank and how easily the truck can get to it. Do not wait for sludge to carry over into the trench or bed, as that is a far bigger job to fix.

Book one if you notice slow drains, sewage odour, gurgling, or boggy or unusually green patches over the trench or bed. It is also worth doing when you buy or sell a property that has no up-to-date service records. Because Central Coast Council requires every on-site system to be registered and hold an approval to operate, a buyer can ask the seller for the approval details. An inspection of the tank and the trench or bed is priced on the size of the system and how much of the disposal area needs checking.

Mostly, what has failed. A baffle, lid or riser repair sits at the lower end. Fixing a partly clogged absorption trench or evapotranspiration bed costs more, and replacing one costs more again. A fault caught early usually costs well below a full system replacement. If the trench has failed, a pump-out system is not an automatic fallback. Central Coast DCP 2022 only allows one for an existing building where the system is failing and there is not enough room for a replacement, or no other workable option.

Usually when the tank is worn out, or the trench or bed no longer takes the effluent even after repairs. An AWTS is one replacement option. For development on flood-prone land, Chapter 3.3 of Central Coast DCP 2022 requires the treatment tank to sit above the 1% AEP flood contour (a flood with a 1% chance of occurring in any year) and the land application area above the 5% AEP contour. In defined drinking water catchments, systems are not to sit below the 1% AEP contour. Council's on-site sewage page says the old tank must be decommissioned under NSW Health Advisory Note 3. Price turns on system size, access and how much trench or bed work is needed.

Not in any practical sense, because the waste has to be taken away and disposed of. Here, septic effluent and septage tankered to Council's sewage treatment plants come under Central Coast Council's Liquid Trade Waste Policy, adopted 27 June 2023. The transporter is a Category S discharger: they need Council's prior written approval and pay an annual fee plus a per-kilolitre charge, with separate charges for septic effluent and for septage.

A conventional septic tank lets solids settle and partly break down, then sends the effluent to an absorption trench or evapotranspiration bed, where the soil does the rest. It has few moving parts but needs a periodic pump-out. An AWTS uses a blower to aerate the wastewater, then disinfects it, producing treated effluent that can be irrigated over a set area. It has a pump and blower to look after and needs regular professional servicing, not just an occasional pump-out. If you are weighing up a change from one to the other, say so in your enquiry.