Worm Farm Septic Tank Systems: How They Work and What’s Approved in NSW

A worm farm septic tank treats your household wastewater with worms and bacteria living in a layered filter bed, instead of relying on the slow, sludge-forming process of a plain septic tank. Worm farm systems are legal in NSW: as at 28 September 2026, NSW Health lists four worm-based wet composting systems and one worm-based secondary treatment system on its registers, although Biolytix, the name many people still search for, is not among them.

The catch is that all four of those wet composting systems are accredited as primary treatment only. In plain terms, that puts them in the same category as an ordinary septic tank for the purposes of what your council will let you do with the effluent.

How a worm farm septic system works

NSW’s Office of Local Government calls these wet composting systems, and its 2025 guidelines note they also go by vermiculture systems, worm-farm systems or biological filter systems. The “wet” part matters. Unlike a waterless composting toilet, which only takes toilet waste, a wet composting system takes the whole wastewater stream from the house: toilets, showers, laundry and kitchen.

In most designs, wastewater lands on a raised bed of layered filter material sitting over an empty space at the bottom. Worms, bacteria and other small organisms live in that bed and break down the solids into humus (worm castings). The liquid trickles down through the layers, collects in the void at the base, and either drains out by gravity or gets pumped from a small well to the land application area. A tall vent pipe, sometimes with a wind-driven ventilator or a fan, draws air through the bed so it stays aerobic.

The details vary by brand. The A&A system’s filter bed is layers of plastic drainage material under the compost pile; the WormSmart Genesis uses plastic mesh and geotextile bags over an effluent chamber, with a submersible pump on float switches; the tiny-house Wormlet uses a removable stainless steel basket to catch the solids.

Two features set these systems apart from a conventional tank:

• Food scraps can go in. The OLG guidelines note that wet composting systems can accept kitchen food scraps along with the wastewater. Some, like Wormworx, have a compost bin on the lid for exactly that.
• There’s compost to deal with instead of sludge. Rather than a pump-out truck removing liquid sludge every few years, the composted material in the bed builds up slowly and has to be dug out and buried from time to time.

Which worm farm systems are on the NSW Health registers

Worm farm systems don’t appear on the NSW Health AWTS list. They sit on two separate registers: Wet Composting Systems and Vermiculture composting secondary treatment systems. A council can only approve a new install of an accredited system, so these are the lists that matter. Here’s what they showed when we checked on 28 September 2026.

A few things stand out.

Every wet composting system on the list is primary treatment. The OLG guidelines say it directly: the majority of wet composting system accreditations are currently for primary treatment only, and a primary-accredited system carries the same limitations as a septic tank. The A&A, Genesis and Wormworx certificates allow the effluent to go to a low pressure effluent distribution (LPED) system built to Appendix M of AS/NZS 1547:2012, or to a sub-soil land application system of a type your council approves. The Wormlet certificate lists a sub-soil system only. Spray or drip garden irrigation isn’t on any of those lists.

The manufacturer’s description may not match the NSW certificate. A&A’s own website describes its system as secondary-treatment certified to AS 1546.3:2017. The NSW Health certificate issued on 15 September 2026 describes its output as primary treated effluent. Your council works from the NSW accreditation, so ask the supplier in writing which NSW certificate covers the model being quoted.

Only one is accredited for secondary treatment. The WormSmart Plus is a two-tank package plant: a worm composting primary tank, a sludge and sediment filter, a trickling filter, then compulsory chlorine disinfection. Its certificate allows the effluent to be used for garden irrigation (above-ground spray, mulch-covered surface drip, or sub-surface drip at around 100 mm) or any form of sub-soil application, each subject to council approval. That flexibility comes with AWTS-style obligations, covered below.

Watch the expiry dates. Two WormSmart certificates show 31 December 2026. If you’re planning an install next year, ask the manufacturer whether the renewal has gone through before you lodge your Section 68 application. A&A’s dates don’t quite agree either: the register shows 4 February 2030, while the certificate itself says 4 June 2030.

What happened to Biolytix

Biolytix is still the worm farm name many people search for, and older BioPod units are still in service. Biolytix does not appear on any NSW Health register we checked on 28 September 2026: not AWTS, not wet composting, not vermiculture. A Queensland business that services Biolytix units says Biolytix Australia stopped trading in 2010, and the biolytix.com address now redirects to a New Zealand company’s BioPod product page.

If you own one, that doesn’t by itself make your system unlawful. The accreditation rule governs what a council can approve for installation; an existing system runs under the approval to operate your council issues, and council sets the conditions on it. What changes is that a council cannot approve a brand-new Biolytix install today, and finding someone who knows the system and can source parts takes more effort.

The December 2010 BioPod owner’s manual is still worth reading if you have one. It stated the BioPod was certified under AS/NZS 1546.3:2008 and approved in NSW at the time, and it asked owners to:

• have it serviced annually by a service technician authorised by Biolytix (more often where the council approval says so)
• keep the power on, since effluent won’t pump out without it
• re-inoculate the bed with earthworms if the system sits unused for more than six months
• keep bleach beyond small laundry amounts, drain cleaners, harsh disinfectants, pool water and wipes out of it

Your council’s approval to operate sets your actual servicing conditions, so ask your council for a copy if you can’t find it. Our guide to AWTS brands in NSW covers how existing approvals work for other brands that have dropped off the register.

Maintenance: what a worm farm system actually needs

“No pump-outs” is a common selling point, and it’s partly true: there’s no liquid sludge to pump from the bed. But these systems still need regular attention, and what’s required depends on the treatment level.

Primary-accredited wet composting systems. The OLG model approval conditions require maintenance to follow the manufacturer’s operation manual, so keep that manual with the house paperwork. The guidelines’ minimum requirements are an annual inspection of the ventilation, compost build-up and worm activity, with compost removed as needed. The model conditions also include:

• the vent fan or wind ventilator must run continuously, with easy access for repair
• where there’s a pump, an audible and visual high-water alarm must be installed and kept working
• a permanent notice on the unit recording the commissioning date and when compost was last removed

Secondary-accredited systems (WormSmart Plus). These follow the rules for secondary treatment systems. The certificate requires a minimum 12-month service contract with a service agent employed or authorised by the manufacturer, a service every three months, and a report sent to your council after every service. Each service checks the chlorinator, pump, blower, alarm and irrigation area, and tests chlorine, pH and dissolved oxygen. The certificate also sets an expected service life of 5 years for mechanical and electrical parts and 15 years for the rest.

Compost removal. Unless your council says otherwise, composted material is buried within your property, in ground that won’t be used to grow food for people for at least three months, under at least 100 mm of soil (the Wormlet certificate asks for 300 mm). The certificates also say who may do the emptying: A&A’s allows the owner or a contractor licensed by the council, Wormworx names Zenplumb staff or a contractor acceptable to the council, and the WormSmart certificates name WormSmart staff or a council-acceptable contractor.

Worm farm septic problems to watch for

Intermittent use. Worms need a steady food supply. The OLG guidelines list “limited ability to handle shock or intermittent flows” as a limitation of wet composting systems, and note that systems without recirculation need a regular inflow to keep the worm and microorganism populations alive. That matters for weekenders, holiday lets and properties that sit empty for months. If that’s your situation, our post on septic for holiday rentals in the Hunter Valley covers the wider issues.

Chemical die-off. The biology is the whole treatment. Bleach in quantity, drain cleaners, strong disinfectants and pool water can knock it back; the BioPod manual listed these specifically.

Ventilation failures. A stalled wind ventilator, dead fan or blocked vent starves the bed of air, which is why the ventilation must run continuously.

Pump and power failures. On pumped systems, a tripped circuit or failed pump leaves the effluent chamber filling with nowhere to go. That’s what the high-water alarm is for.

Odour. The OLG’s Easy Septic Guide lists “can be smelly” as a drawback of wet composting systems. A new or persistent smell means something has changed.

The land application area. Wet ground, ponding or sewage smell over the trench are the same warning signs as with an ordinary septic tank; our list of absorption trench failure signs applies here too.

Is a worm farm septic system a good fit for a Hunter block?

It depends mostly on your soil and how the house is used. Because most worm farm systems are accredited for primary treatment, the effluent goes below ground, just as it does from a septic tank. The OLG guidelines’ comparison table notes that primary treated effluent means a lower design loading rate, so a larger land application area, higher buffers and greater soil depth. On heavy clay soils, which are common across parts of the Hunter, that can mean a big trench or bed area. The WormSmart Plus can ease that limit with disinfected secondary effluent, but brings back quarterly servicing and more electrical parts.

A worm farm makes more sense for a permanently occupied home with steady use, enough suitable ground, owners happy to handle compost, and a supplier you can actually reach. The OLG guidelines also list low energy use as an advantage, which helps on off-grid sites.

It’s a harder fit for weekenders with long empty spells, small blocks on heavy clay, and sites where buffers to bores, dams or creeks squeeze the effluent area. For the two mainstream options, see septic tank vs AWTS.

Whatever you choose, installation, excavation, tank setting and trench or bed construction on jobs we coordinate are carried out by licensed plumbing and drainage contractors we work with; their NSW licence number appears on every quote. You’ll also need your council’s Section 68 approval before any work starts.

What a worm farm septic system costs

We don’t publish a price for worm farm systems, and we won’t repeat supplier prices here because they change and depend on the site. Ask the manufacturer for a written quote naming the NSW certificate.

The tank is only part of the cost: the land application area, plumbing and the site and soil assessment all add to it. For comparison, our published ranges for other systems through licensed contractors are $12,000 to $18,000 for a conventional tank with gravity trenches, $15,000 to $25,000 or more for a complete AWTS, and $8,000 to $14,000 for a new absorption trench on its own. Our septic replacement cost estimator gives a rough starting point for your block.

If you’re buying a property with a worm farm or an old Biolytix on it, get it looked at before you sign. A pre-purchase septic inspection runs $250 to $500 and covers the tank’s condition, the lines and the absorption area, with a written report. We don’t hold manufacturer authorisation to service worm farm systems, so for servicing we’ll point you to the manufacturer. For an inspection, call 0468 278 123.

Frequently Asked Questions

Are worm farm septic systems legal in NSW?

Yes. As at 28 September 2026, NSW Health lists four worm-based wet composting systems and one worm-based secondary treatment system on its registers of accredited sewage management facilities. A council can only approve a new install of a system with current accreditation, and you still need your council’s Section 68 approval before installation.

Is Biolytix still approved in NSW?

Biolytix does not appear on any current NSW Health register, based on what we checked on 28 September 2026, so a council cannot approve a new Biolytix install today. An existing Biolytix system runs under the approval to operate your council issues, so check that approval, or ask council for a copy, for the servicing conditions that apply to your property.

Do worm farm septic systems need pumping out?

There’s no liquid sludge to pump from the filter bed, but composted material builds up and must be removed and buried from time to time. The usual NSW condition is burial on your property under at least 100 mm of soil, in ground not used to grow food for at least three months, unless your council directs otherwise.

Can a worm farm septic system water the garden?

Only if it’s accredited for secondary treatment and your council approves it. All four wet composting systems on the NSW register are accredited as primary treatment, which limits the effluent to a sub-soil land application system or an LPED system, the same as a septic tank. The one worm-based secondary system on the current register, the WormSmart Plus, allows irrigation subject to council approval and requires quarterly servicing.

What kills the worms in a worm farm septic system?

Large amounts of bleach, drain cleaners, harsh disinfectants and pool water can damage the biology, as can long periods of no use and power or ventilation failures. Follow the chemical list in your manufacturer’s owner’s manual.

Is a worm farm septic system suitable for a holiday home?

It can be a poor fit. The NSW Onsite Wastewater Management Guidelines list limited ability to handle intermittent flows as a limitation of wet composting systems, because worms need a steady food supply. If the house sits empty for long periods, ask the manufacturer how the system recovers and whether re-seeding with worms is needed.

Sources and further reading

• NSW Health, Accreditation of sewage management facilities: the list of separate registers, including Wet Composting Systems and Vermiculture composting secondary treatment systems, and the rule that councils may only approve accredited facilities.
• NSW Health, Register of wet composting systems: A&A, WormSmart Genesis, WormSmart Wormlet and Wormworx entries, certificate numbers and expiry dates, current as at 21 September 2026.
• NSW Health, Register of vermiculture composting secondary treatment systems: the WormSmart Plus entry and certificate STS-VC001.
• NSW Health certificate WetCT020, A&A Worm Farm Waste System: how the system works, primary treated effluent, permitted uses and compost burial rule.
• NSW Health certificate WetCT027, WormSmart Genesis: design, primary classification, alarm requirement and emptying conditions.
• NSW Health certificate WetCT021, WormSmart Wormlet: 3-person, 550 litre a day tiny-house model, stainless steel basket, primary classification, sub-soil disposal only, 300 mm compost cover.
• NSW Health certificate WetCT026, Wormworx: primary-only classification, tank options and emptying conditions.
• NSW Health certificate STS-VC001, WormSmart Plus: secondary treatment design, quarterly servicing, 12-month service contract, service life and permitted irrigation uses.
• Office of Local Government, Onsite Wastewater Management Guidelines (April 2025): section 5.3.2 on wet composting systems, section 6.1.1 on intermittent flows, Table 7-2 advantages and limitations, model approval conditions A2.1.6 and A3.1.7, Table A5-1 annual inspection items and compost removal (A5.3).
• Office of Local Government, The Easy Septic Guide: pros and cons of wet composting systems for homeowners.
• A&A Worm Farm Waste Systems: the manufacturer’s own description of its system and its AS 1546.3:2017 claim.
• WormSmart: the manufacturer’s description of its Genesis (primary), Plus (secondary) and Wormlet models.
• Biolytix Solutions Servicing and Maintenance: statement that Biolytix Australia stopped trading in 2010.
• WaterFlow NZ, BioPod systems: the page biolytix.com now redirects to.
• Biolytix BioPod owner’s manual, December 2010: annual servicing, earthworm re-inoculation after six months unused, and the list of chemicals to keep out.