Checking galvanised water pipes

Galvanised PipesThey are grey in colour and usually roughly 25mm (one inch) in diameter. If your plumbing system has not been upgraded in the last 40 years, it is likely you have galvanised pipes installed in your home.

If you own a high-set home: 

You may be able to see your water pipes attached to the bearers and joists which support the floor boards and determine whether they are galvanised iron pipes.

If you have a low-set home:

You may be able to identify if you have galvanised pipes by carefully digging around the base of an outside garden tap. Pipes which are dull grey in colour or have a rough, scaly and rusty appearance are most likely galvanised, whereas those that have a smooth surface and which are coloured orange or brown will most likely be copper pipes. Polyethylene pipes are generally black and may have blue longitudinal lines. Carefully scratching the surface of the pipe may help to identify the material type.

As they age, galvanised pipes have a tendency to corrode internally, causing oxidised iron to form in the pipeline. While this is generally not harmful to human health, you may notice some of the following if your pipes are corroded:

  • a metallic taste in your water
  • rust stains on the outside of your pipes
  • particles floating in your water
  • poor water pressure (as a result of the oxidised iron blocking the pipes)
  • discoloured water (may be intermittent)
  • stains in your sink or toilet as well as on appliances like washing machines
  • a blocked water filter. 

Clogged galvanised pipes

You may be able to confirm if the inside of your galvanised water pipes are corroded by following these simple steps first thing in the morning before anyone uses the shower or toilet.

  1. Fill a small white container with water and take note if the water is discoloured or has small particles of ‘rust’ in it.
  2. If the water is discoloured or particles are visible, the inside of the pipe may be corroded.
  3. Repeat this procedure one or two times.
  4. If your initial observations are confirmed and the water is discoloured or particles of rust are visible, it may be worthwhile to engage a licensed plumber to remove a small section of pipe and check the inside of your water pipes to determine when they might need to be replaced.

While the metallic water taste and discolouration caused by corroded galvanised iron pipes is not a health issue (and therefore does not need to be fixed immediately), many people do find it unpleasant.

To manage this issue on a daily basis:

  1. Run affected taps for one to two minutes first thing in the morning to clear any water in your pipes.
  2. You may also need to do this at other times of the day, particularly if you leave the house for a few hours or have not used water for a reasonable length of time.

The cost of running taps for five minutes is 30 cents and, on average, uses 75 litres of water. To avoid waste, this water can be used on your garden. Please be aware running the tap will only clear the discoloured water; it will not fix the cause of the problem.

Dirty water running from tap into a bucket to clear pipesClear water running from tap into bucket to clear pipes after water outagePouring leftover dirty water into garden


The only way to completely overcome issues associated with the corrosion of galvanised water pipes is to have the pipes replaced. If you wish to do this, it is advisable to install new pipes made from an alternative material, such as polyethylene or copper. A licensed plumber can carry out these works for you.

Unitywater routinely replaces water meters when they are nearing the end of their life cycle. These replacements are preventative maintenance, to ensure the water meter on your property is accurate and in full working order. If we need to replace a water meter on your property, we will try to connect the new water meter to your existing pipes. However, if you have galvanised iron pipes that have corroded, it may not be possible to do so.

In this case, we will run an above-ground polyethylene pipe from the new meter to your home (installation funded by Unitywater). This is only a temporary service and it is the property owner’s responsibility to have a permanent service installed and to fund any associated costs. Under the Plumbing and Drainage Act 2002, plumbing and drainage works around your home must be carried out by a licensed plumber.