Small bore wastewater and macerator pump installation procedure

In cases where venting to atmosphere is not possible, and the small-bore pumping apparatus does not hold a volume of water at any time, manufacturers may specify optional alternative venting arrangements such as a carbon filter vent.

Alternative venting will only be acceptable for dry, no reservoir, small-bore pumping apparatus which receive either one kitchen sink or one hand basin. All alternative venting products must be watermarked and meet the manufacturer’s specifications and instructions.

Pump discharge pipes must comply with AS/NZS 3500.2:2015 and discharge to one of the following locations:

• an inspection chamber
• a boundary trap shaft
• a stack below the lowest fixture connection on any floor
• a drain or combined discharge pipe, providing the connection is at least 2.5 metres from any other connection
• downstream of a reflux valve, or at least 2.5 metres upstream of a reflux valve
• a minimum of 1 metre downstream of a boundary trap.

The National Construction Code Series Volume Three, Plumbing Code of Australia (PCA), Part C2 specifies the objectives and performance requirements relating to installing sanitary drainage systems. AS/NZS 3500.2 and AS/NZS 3500.5

Sanitary plumbing and drainage are the ‘deemed to satisfy’ documents listed in Part C2 of the PCA, which contains sections on pumped discharges and rising mains.

The pumping method will include a wet well (including submersible pump), holding tank (with pump) or small bore macerator type unit.

• Wet wells must be fit for purpose and installed in accessible positions.
• Holding tanks must be constructed of authorised materials including precast or cast in situ concrete, corrosion resistant metals or glass reinforced plastics.
• Covers must have access openings, with removable airtight covers sized for maintenance purposes.

Plumbers must contact SA Water (opens in new window) to find out the maximum flow rate from a pump into a sewer connection.

The outlet pipe from the wet well or holding tank must discharge to one of the following:

• an inspection chamber
• a boundary trap shaft
• a stack below the lowest connection on any floor
• a drain or combined discharge pipe, providing the connection is at least 2.5 metres from any other connection
• downstream of a reflux valve or at least 2.5 metres upstream of a reflux valve
• a minimum of 1 metre downstream of a boundary trap
• directly to the water entity’s sewer, where approved by the entity.

• Materials used for the discharge pipe or rising main from a wet well or holding tank must be fit for purpose and shall comply with the relevant parts of Section 2 of AS/NZS 3500.1.
• Buried discharge pipes or rising mains must be enclosed in a sleeve or continually spirally wrapped with identification tape. The sleeving or spiral wrapping must be identified for the full length with the wording ‘sewer rising main’ or ‘pumped discharge pipe’ in accordance with AS 1345.
• Above ground discharge pipes or rising mains must be identified in accordance with AS 1345.
• Identification tape with the wording ‘sewer rising main’ or ‘pumped discharge pipe’ must be installed on the pipe in a visible position along the length of the pipe (not wrapped around it) and fastened to the pipe no less than every 3 metres.

Plumbers must provide a certificate of compliance to the customer and the Office of the Technical Regulator (OTR) within 7 days of finishing plumbing work, except for:

• changing tap washers
• clearing blocked sanitary drainage pipework not exceeding 50 mm in diameter
• replacing, altering, repairing, maintaining, or disconnecting domestic tapware.

Penalties for not supplying a plumbing Certificate of Compliance include warnings, disciplinary interviews, and potential legal action, and are detailed in the Water Industry Act 2012.

When it is not possible to have a 50 mm vent discharging into the atmosphere, plumbers must send a performance solution detailing the alternative venting method to the OTR.

Performance solutions aren’t permitted when soil fixtures are connected to the pump apparatus. An alternative venting method must achieve the same outcome as the requirement for a vent to the atmosphere.

Performance solutions sent to the OTR must include:

• A covering letter from a recognised expert, e.g. pump manufacturer or hydraulic consultant, outlining the proposed performance solution and how it meets the performance requirements of the PCA. If carbon filters or other venting methods are included as a component of the performance solution, a maintenance schedule for the venting method must also be included.
• A letter from the property owner accepting the performance solution and confirming they will do the necessary scheduled maintenance.

The OTR will send a Notice of Advice letter confirming the performance solution to the property owner. The Notice of Advice will be registered on the South Australian Integrated Land Information System and provided to any interested party on request.