Master Plumbers Blog

Fixing a Blocked Drain in Dunedin: When to Call a Drainlayer

You begin to notice that the shower tray is starting to hold water, while the kitchen sink starts to gurgle. A blocked drain is usually the culprit, and in Dunedin, you can usually sort this in ten minutes or so. But sometimes, these inconveniences may be the first sign of a cracked pipe under the lawn. Mains Plumbers has worked on Dunedin homes and buildings since 1947. Our Dunedin drainlaying team clears both kinds of problems.

Quick Summary

A blocked drain can usually be cleared with a plunger or a hand drain snake. You may need to call a drainlayer if more than one fixture backs up, like a basin or shower, or when the gully trap overflows. Smelly sewage coming from the sink or bathroom, or a stubborn drain that keeps getting blocked within days, are also signs that a drainlayer visit is needed.

You can clear a blocked drain yourself. But repairing or altering a drain, or even taking off a trap, is restricted work in NZ, left to professional drainlayers. For 2026, basic drain clearing sits at $120 to $250, and a job needing hydro jetting is $350 to $1,800. In Dunedin, the property owner is generally responsible for maintenance and upkeep of the drain, up to the council main.

What You Can Safely Clear Yourself

A single slow drain clogged with hair or soap scum near the plughole is yours to try. This is the best way to unblock a drain at that stage:

Clear the strainer. Pull hair out of the plughole or shower grate by hand. Clogged drains in a bathroom often start right here.
Use a plunger. Place a damp cloth over the overflow to secure the plunger, then firmly plunge several times.
Flush the drain with hot water. Use the hot tap rather than pouring boiling water from the kettle, which can soften plastic waste pipe if it sits behind a blockage.
Try using a hand drain snake. A typical hardware-store snake can hook and grab a hair blockage a regular plunger can't reach.

That's how to unclog a drain with what's already in the laundry cupboard. Don't undo the trap under the sink, though. The Plumbers, Gasfitters and Drainlayers Board specifically mentions that unfixing any trap is something that a homeowner can't and must not do. This is restricted work, reserved only for licensed plumbers.

As much as possible, avoid using the usual supermarket chemical drain cleaners. It rarely moves a solid blockage, and repeated use can eventually damage pipes' inner linings.

Signs a Blocked Drain Needs a Drainlayer

Call a drainlayer once the problem is bigger than one fixture:

More than one fixture is slow or backing up, such as the toilet gurgling when the shower runs.
The gully trap is overflowing. That's the grated outlet outside where your waste pipes discharge into the drain.
You can smell sewage indoors or around the gully.
The same drain blocks again within a few weeks of clearing.

The blocked gully trap solutions you can safely try are simple: lift the leaves and silt off the grate, then run a little water. If it doesn't drain, the blockage is further down.

Wastewater coming up through a gully or floor waste is an urgent job for an emergency plumber, day or night. Stop running water and call. Main-line blockages cost more than slow drains in one room: a 2026 national cost guide puts major sewer or stormwater blockages at $600 to $2,000 or more.

Why the Same Drain Keeps Blocking

A blocked drain that keeps coming back is usually a sign of a greater problem with the pipes. Tree roots are the common cause. These roots can find their way in a crack or joint and grow into a mat. Though you can clear them, they tend to grow back.

The Dunedin City Council says the landowner is generally responsible for the pipe all the way to the council sewer main, including under the road. For landlords and property managers, roots in the lateral under the footpath are still part of your drainage system, not the council's.

What a Drainlayer Does That You Can't

A drainlayer focuses on the root cause of the blockage problem, and not just its symptoms. For stubborn blockages that no DIY can solve, this usually means that the drainlayer may do any of the following:

CCTV drain inspection. A camera on a push rod shows exactly where the roots or the crack are. Know the signs you need a drain inspection.
Hydro jetting. High-pressure water cuts through grease and roots. See how hydro jetting clears a drain.
Repair or relay. A broken section is dug up and replaced.

That last step is restricted by law. The Plumbers, Gasfitters and Drainlayers Board says homeowners can't do any work involving the "installation, alteration or repairs to a drain". It needs someone with a current drainlaying licence, so ask to see it first. A certified drainlayer can show it on a phone app or a physical card.

How Much Does a Plumber Cost to Unclog a Drain?

Basic drain clearing in New Zealand typically costs $120 to $250, according to a 2026 guide to drain unblocking costs from Auckland firm Extreme Plumbing. Here's an estimated cost for plumber services to unclog a drain in NZ in 2026:

Job	Typical cost (NZD)
Basic drain clearing	$120 to $250
Drain snaking	$180 to $450
CCTV drain inspection	$250 to $600
Hydro jetting	$350 to $1,800
Emergency call-out fee	$180 to $350+

Also expect to spend anywhere between $350 and $2,000 for clearing stormwater drainage, which carries rain from your spouting and downpipes, depending on the scope of work. The above guide didn't mention whether GST is included. Since it is also written with Auckland in mind, consider it as a national range rather than a local Dunedin estimate. We'll tell you upfront what the job needs and what it is likely to cost before we start.

Why a Drainlayer Who Knows Your Section Helps

Someone who has worked on your drains already knows where the gully and inspection points are. Mike Mains is the third generation of his family to run the business, and Brockville School has used the team for ongoing drainage work.

Roberta Coutts of King Edward Court puts it plainly: "You can ring up and talk directly to the boss; he knows what you're talking about, he knows the work, the buildings."

We work from Mosgiel across Dunedin, from Middlemarch and Dunback to Palmerston and Milton, and the phone is answered 24 hours a day.

Frequently Asked Questions

How much does it cost to unblock a drain in NZ?

Usually $120 to $250 for a straightforward clear, based on a 2026 national cost guide. A blocked drain that needs hydro jetting runs $350 to $1,800. GST status isn't stated.

How much do plumbers charge to unblock drains?

Most charge a call-out or first-hour fee plus time, with a jetter or camera added if needed. After-hours call-out fees run $180 to $350 or more in the same guide.

How to unclog a drain naturally?

Start with hot tap water, then a cup of baking soda followed by a cup of vinegar. Leave it for 15 minutes and flush with hot water. It'll lift light soap scum, not a solid blockage.

How to unblock a drain without a plunger?

If visible, you can pull the hair or any debris out of the plughole by hand. Using a drain snake, feed it into the drain and catch what's below. Never remove the trap under the sink; keep it in place. Removing a sink trap is restricted plumbing work.

Does baking soda unblock drains?

On its own, not really. A baking soda and vinegar solution may be effective in loosening grease, but it will never remove hair clumps if the latter is the culprit. If none of these methods work, the blockage is deeper than the plughole.