In August 2014 after a large number of issues where every other job we attended was a leaking water main, I concluded that all of them were caused by incorrect installation. In our monthly newsletter and in a blog I highlighted that negligence causes plumbing emergencies.
Since 2014 nothing has changed with polypipe leaking water main repairs being a constant source of work. The number of defective installations in new homes reinforces that a City of Gold Coast plumbing inspection is not a guarantee.
It is positive to see that the Department of Housing and Public Works issued Building And Plumbing Newsflash 558 on 13 March highlighting issues on the correct selection and installation of polyethylene (PE) pipe which is commonly called polypipe or blue line poly, used as a material for water supply installations. The QBBC also raised the matter in a blog Health and safety concerns relating to PE pipes, or ‘blue line poly’.
The issues we see every day on almost every leaking water main has been highlighted in the Newsflash with the Department stating “…..has become aware of issues associated with PE pipe including pipe leakage resulting from material splitting and holes developing in the material. Although the direct cause of these failings has not been determined, it is timely that the department issue advice on the correct selection and installation of the product.”
When installing a polypipe water main a licenced plumber must ensure that it is done so in accordance with the Plumbing Code of Australia and the referenced standard which is AS/NZS 3500.1-2015. These are not options but are law as per the Plumbing and Drainage Act 2002.
The following clauses in AS/NZS 3500.1-2015 must be complied with in regard to installing any underground water main:
- Clause 2.3 Selection and Use of Materials and Products – this clause states that materials and products used in a water service shall be selected to ensure fitness for their intended purpose and goes on to list all those factors so that there is no doubt.
- Clause 5.2 Proximity to Other Services – this clause is very specific on hoe water service pipes are to be separated from any other underground services including gas or electrical and drainage pipes. The separation distances range between 100mm and 600mm depending on the size of the water service and the type of the neighbouring service. The specific requirements are laid out in clauses 5.2.1 through to 5.2.10.
- Clause 5.9 Depth of Cover – this clause once again is very specific in stating the depth at which underground pipes shall be with table 5.9 giving specific loading conditions and the minimum cover or depth which ensure the pipe is protected. In most cases the minimum depth is 300mm unless there are vehicle loading factors which then can require the pipe to be at 750mm depending on what the ground surface is.
- Clause 5.10 Bedding and Backfill – this clause is the one we see most commonly ignored on the Gold Coast and is what causes the entire leaking water main to require replacing. The clause is very specific in stating that the pipe must be surrounded entirely with a minimum of 75mm of compacted sand or fine grain soil with no hard edged object in contact with the pipe. Again very specifically it states the final backfill shall be free from rock, hard matter, organic matter and be broken up to ensure that there are no soil lumps larger than 75mm.
- Clause 5.11 Installation in Contaminated Areas – this clause states exactly what is a contaminated area and that a pipe laid in a contaminated area shall be installed in a water tight, corrosion resistant conduit.
The clauses above are quite specific on how your water main should be installed. They are specific requirements under the Plumbing and Drainage Act 2002. They are not options the plumber can choose to opt in and out of.
If you suffer a leaking water main and it is not installed as per the above clauses the licensed plumber installing it has done so knowing it is non-compliant and that it is reasonably foreseeable that failure and damage will occur over time. Very simply this is negligence.
