Commercial Plumbing in Dunedin: What It Covers

If you run a business in Dunedin, the plumbing in your building isn't the same job as the plumbing in your home. Commercial plumbing handles more fixtures, heavier daily use, and longer running hours.

It also carries duties a homeowner never meets. A backflow preventer is one example: it's a specified system, and that puts ongoing obligations on the building owner.

This page covers what the work includes, how the law treats it, and when to call a commercial plumber rather than book an ordinary callout. We've worked on Dunedin buildings since 1947.

Quick Summary

Commercial plumbing covers the water, waste, gas and drainage systems in a building used for business rather than as a home. That includes installation, repairs, upgrades and regular maintenance.

Behind it sit the same trades that serve a house. What differs is the scale of the systems, how hard they're used, and what the building owner then has to do.

Where a building has specified systems, such as an automatic back-flow preventer connected to the potable water supply, the Building Act 2004 requires a compliance schedule and an annual building warrant of fitness. That duty doesn't apply to single household units.

What commercial plumbing actually covers

A commercial plumbing service covers the building's water supply, hot water, sanitary plumbing, gas, drainage and stormwater, often several of those at once during a fitout or an upgrade. It reaches well beyond a leaking tap.

Typical work includes:

• Hot water systems, including heat pump hot water cylinders, mains pressure conversions and continuous flow water heater upgrades
• Stormwater, spouting and downpipes on a larger roof area
• Waste pipe upgrades where the line was never sized for current use
• Surface water problems around yards and car parks
• Backflow prevention on the potable water supply
• Plumbing inspections before you buy a commercial property
• Emergency plumbing services and urgent repairs

Buildings differ. A restaurant carries different demands as compared to a workshop or an office.

The scale of work also varies across different commercial buildings. For example, you only need light commercial plumbing if yours is a cafe, a dental suite, a shop, or a two-storey office. The scope of work for these commercial buildings is relatively larger than that of a typical house, but their systems are smaller than those of industrial sites. Most businesses in Dunedin sit somewhere in this category.

It is definitely worth knowing which category your building belongs to before you make enquiries among various commercial plumbing companies. Some companies cater to large-scale industrial sites and eventually pass on smaller jobs to subcontractors.



It also helps to be familiar with backflow issues and how to prevent them. Both Schedule 1 of the Buildings Regulations 2005 and the MBIE's guidance for building owners require the use of automatic backflow preventers on a potable water supply. These should be explicitly included along with sprinklers and lifts as part of any specified systems. Once these are in place, council also requires regular annual inspection, maintenance and reporting.

How commercial work differs from domestic plumbing

The trades are much the same. The setting is not. The same firm often does both: residential plumbing services and commercial work draw on the same trades and frequently the same team, which is why a plumber who covers home plumbing services can work on your premises, provided they hold the right licence class for the job.

The obligations are where the two-part company. Guidance from the Ministry of Business, Innovation and Employment states that the compliance schedule requirement "does not apply to single household units (residential homes) unless they have a cable car."



What New Zealand law asks of a commercial building owner

Who may do the work. Only an appropriately licensed person may carry out restricted sanitary plumbing, gasfitting or drainlaying. The Plumbers, Gasfitters and Drainlayers Board explains that registration on its own is not authorisation to carry out restricted work. The licence provides that.

Registration runs in three classes: restricted, plumber or gasfitter or drainlayer, and certifying. Anyone below certifying works under a named certifying supervisor, who remains responsible for the work. These certifications are still needed even if the work is being done in a house or a warehouse. As a building owner, it's good practice to check with your service provider if they hold these required licenses before they begin any kind of work.

What the owner must do. If your building has specified systems, you'll need a compliance schedule and an annual building warrant of fitness. These are requirements alongside other general health and safety obligations you need to comply with. A specified system that has not been inspected is a red flag and may pose a risk to your building's occupants.

An independent qualified person certifies the inspection and maintenance. MBIE describes that person as "a person (or firm) approved by a council as qualified to inspect, maintain and report on specified systems." You keep the reports, log books and test certificates with the compliance schedule for at least two years

If you've taken over a building recently, the compliance schedule should have come with it, and the council holds a copy if you can't find yours.

If you're unsure whether your building has a specified system, the compliance schedule is the place to check first.

When downtime costs money

For a business, the cost of a plumbing issue is not entirely measured in terms of the cost that it entails, but the trading hours it loses if the problem remains unresolved.

We make ourselves available 24/7 to make sure that you can avoid such a scenario. Having an emergency commercial plumber available helps reduce any worry that you will be flooded with after-hours calls once your home.

Our aim is to tell you what a job needs before we start, what it's likely to cost, and how long your water or gas will be off. That's the part you can plan around. We understand that both your staff and even customers need to work around this shutdown schedule, if any. Letting them know in advance builds trust and shows respect to their schedules as well.

Some plumbing issues can safely wait until the next working day. A dripping tap in a staff kitchen is an inconvenience and can wait for some time. But burst pipes, having no hot water source for food service establishments, or a blocked line backing up into a customer area, may put your potable water supply at risk and endanger your occupants.

If yours is a commercial site, resolving such issues should not be delayed and may also means temporary closing your establishment or operating in a reduced capacity.

Most business owners can tell which sort of plumbing problem they're looking at. If you're not sure, describe what you're seeing when you give a call. This is the better route, rather than guessing.

Describe the problem as you see it, and it will help us know if plumbing work needs to be done immediately, or if it can be done the next day. Our goal is to ensure that your commercial building still operates worry-free so that you don't need to have reason to close temporarily.

Where the work touches a specified system, we'll say so. It affects what your building needs from you once the job is finished, and it's easier to arrange an inspection while the contractor is still on site.

Working across Dunedin and Otago

We work with commercial owners and business operators throughout Dunedin and the wider Otago region, including Mosgiel, Middlemarch, Dunback, Palmerston and Milton.



Mains Plumbers was founded in 1947, and Mike Mains is the third generation of the family to run it. Continuity counts for more on a commercial building than on a one-off house call: someone who has seen your plant room before knows where the isolating valves are. We cover plumbing and drainage on commercial sites across the region, and our team works alongside other trades on site, which helps keep a project moving.

You can see the range of commercial plumbing services we cover in Dunedin, or browse our services for everything else.

Frequently asked questions

What is the difference between commercial and domestic plumbing?

The trades are the same; the obligations are not. Domestic plumbing serves a single household. Commercial buildings are expected to have heavier demand and larger fixtures.

This makes commercial plumbing even more important, especially if specified systems are present. The building owner is more responsible for ensuring compliance with standards, as compared to an owner of a single household unit.

How do commercial bathroom requirements differ from residential?

Commercial bathrooms take continuous use from staff, customers, and visitors. Fixtures and drainage are specified for far heavier duty than a home bathroom. Where a backflow preventer protects the potable supply, it becomes a specified system with annual inspection and reporting attached.

What are the best options for commercial plumbing in my area?

It's the question business owners ask most often: what are the best options for commercial plumbing services in my area? Commercial plumbing companies vary more than they look from the outside. Choose a licensed contractor with experience on commercial premises, and ask who will actually carry out the work and what licence class they hold. A firm covering plumbing and drainage in-house, with its own gas fitters, will usually cause less disruption than one subcontracting two trades out of three.

Great service on a commercial site is mostly communication: being told what the job needs, what it will cost, and when your water goes off. Ask other businesses nearby who they use: a contractor who comes highly recommended by people running similar premises tells you more than a good website. If your building has a compliance schedule, ask how the work fits the systems already listed on it.

What does commercial plumbing maintenance involve?

It depends on the type of building. But it usually involves regular checks on hot water systems. It also includes checking into drainage, stormwater, and any backflow issues. Having a regular, preventive maintenance schedule will definitely cost you less than trying to solve a water leak problem at 2 in the morning. If you're following a routine compliance schedule, then the required inspections and records stay current.

The short version

Commercial work involves the same trades as domestic plumbing, but the building and its obligations are different, and most of those obligations sit with the owner.

If your premises have a backflow preventer or another specified system, make sure you know the maintenance and compliance requirements. Restricted work also needs an appropriately licensed person.

Not sure what your building needs? Drop us a line or call 03 488 6000.

References:

Ministry of Business, Innovation and Employment. (n.d.). Owners' responsibilities to ensure their buildings are safe to use. Building Performance. https://www.building.govt.nz/assets/Uploads/managing-buildings/bwof-guidance/bwof-guidance.pdf

Plumbers, Gasfitters and Drainlayers Board. (n.d.). Understanding registration and licence classes. https://www.pgdb.co.nz/media/mizhvdit/understanding-registration-and-licence-classes.pdf