Plant trees with your pipes in mind
A tree's roots supply it with the water and nutrients it needs to survive. However, if a tree discovers its next meal is hidden in either your household or Metrowater's public sewer pipes, you could be facing problems.

As trees mature, so do their roots, which can enter sewer pipes and damage them, obstructing the flow and eventually causing a blockage. Root damage can also allow stormwater to enter the pipes. During heavy rain this extra water can overload the wastewater system, causing it to overflow into waterways, the street or even your back yard. This represents a significant environmental and public health risk. There are also financial costs to consider - if the problem occurs in your private sewer pipes, it's your responsibility to have it fixed.

Avoiding damage to your sewer pipes
The key is to plan ahead. Avoid planting species that are likely to cause problems and plant trees as far away from pipes as possible.

Before planting, find out where your sewer pipes are located so that you can stay clear of them. Many homeowners have a plan of their property, which shows the location of sewer pipes and other plumbing. If you don't, contact Auckland City Environments on (09) 379 2020 to obtain a copy of your plan. At the same time, check the location of the public sewer pipe running past the front of your property.

Make sure the tree you have chosen is appropriate for where you want to plant it. Your local nursery can help with this or you can consult a gardening guide. It's important to find out how far the tree's roots will travel - they usually extend about one and a half times the distance of the adult plant's branches and up to 1.5 metres deep. Don't plant large, fast-growing trees with vigorous root systems near sewer pipes. If you need to plant vegetation over or near a sewer line, choose shrubs, grasses or small trees with less extensive root systems.

More information about planting trees on urban sites, including a list of some potentially suitable tree species for city gardens, is available in Metrowater's fact sheet.