How to tell if my drain field is failing

Are you having problems with your septic system? Then you might be experiencing the effects of drain field failure. Many homeowners leave issues like this unsolved for far too long, and it can lead to sewage backup, which can flood your premises, creating an unexpected repair expense.

The drain field is an important part of the septic system. Drain field failures can cause huge issues for a septic system. Read on for a list of signs to watch out for when detecting drain field failure before it reaches a critical stage.

Water Backup

One of the main signs of a drain field failure is when water backs up in your drains. If you have a normal amount of water in your toilet but you still need to flush it multiple times, this could be a key sign of a failed drain field.


If a septic odour is hanging around your backyard, or rising from your drains, this is a clear sign you might have drain field failure. This smell is caused by the drain field’s liquid waste collecting in the surrounding soil.


One way to detect if your septic system has failed is by looking in your back garden for damp spots, puddles or even areas which are greener or have a denser growth of grass. If it hasn’t rained and there are still puddles, this may be a sign of a drain field failure; as your liquid waste is running out of space within the septic tank and is beginning to surface in your garden.


Gurgling or ‘burping’ sounds coming from your drains is an early sign that the drain isn’t venting properly. You might also hear these noises coming from other plumbing fixtures, even the toilet. This means you have some sort of blockage in your drainage system.

Sludge or slime

A sign of more serious problems is the presence of a black slimy substance on the ground above your septic tank or a significant layer of sludge or scum inside the tank.

What is happening underground?

When the home’s wastewater enters the septic tank it pushes a portion of the tank’s contents into the drain field, and a functional drain field will hold the water until it can be absorbed into the surrounding soil. Drain field failure can be caused by the household using more water than usual. When the water sits in the drain lines too long it forms a slimy, bacterial coating on the walls. This stops the wastewater from draining properly.

On days when a household is using a lot of water the lines are never able to dry out, so this causes water backup. Another issue that can occur is excessive amounts of grease, soap and solids collecting in the bottom of the septic system. When large amounts of water flush through it, the drain field can become easily clogged.

Some outside factors which can also trigger drain field failure include:

  • Not cleaning or pumping the septic tank often enough.
  • The drain field pipes breaking or collapsing.
  • Cars or heavy equipment compacting the soil.
  • Tree roots breaking into the drainfield and piping.

Once a problem with your drain field has been identified, it is time to call the experts. At Express Drainage Surveys our skilled team investigates any drainage issues and provide a professional solution to customers all over the South East. Get in touch today to find out more.