Septic tank leaking above ground

What an above-ground leak means for your septic tank, and the steps to put it right.

Sam WarrenUKDP co-founder
Published4 May 2020
Updated26 Oct 2026
Read time4 min

Key takeaways

A septic tank leaking above ground, through the lid or manhole covers, means the drainage system is full beyond its usual capacity.
The likely cause is damage to the drainage system or a failed soakaway or drainage field.
If the tank has been damaged, your buildings insurance policy may cover the cost of putting it right.
A system that has failed through age, with no damage, is likely to need some or all of it replaced.
Get the tank emptied first, ask the operator what they noticed, then have the system inspected.

Septic tanks take wastewater from your property’s toilets, showers, baths, sinks and kitchen appliances. To find out what happens to it once it’s there you can read our Guide to How Your Septic Tank Works.

Wastewater from your toilets, sinks and appliances should flow through the tank and out to a soakaway, out of sight and out of mind. When it starts surfacing through the lid or pooling on the lawn, the system has filled beyond the level it can cope with.

Is your septic tank leaking above ground? Is there soggy ground around your septic tank?

Let’s work out why your septic tank isn’t working as it should and what you can do to sort it out as quickly as possible!

If you’ve noticed that your septic tank is leaking above ground, possibly through the lid of the septic tank or other manhole covers, it is a sign that the drainage system is full beyond its usual operating capacity.

What can cause this, and what do you need to do next?

Our recommended first port of call at any sign of septic tank problems is to get your tank emptied. It’s possible that the tank emptying operator might be able to give you some clues as to what’s happened to the septic tank and caused it to leak above ground. It will also give you some respite from the problem, to give you some breathing space to work out what’s happened and what needs to be done to sort it out.

Unfortunately, if your septic tank is leaking above ground, there’s a good chance that there might be some sort of damage to the drainage system, or that any soakaway or drainage field connected to the septic tank has failed. This might sound worrying, but it’s best to get the problem inspected as soon as possible, and to get matters in hand to prevent the situation from getting any worse. Once you have had the septic tank emptied, ask the operator if they’ve noticed any issues. Then, it’s time to get the system thoroughly inspected to find out exactly what’s going on.

Did you know?

It’s possible that, if the septic tank has been damaged, the costs of putting things right may be covered by your existing buildings insurance policy. UKDP are experts in both septic tanks and helping with insurance claims, so we can handle everything for you from start to finish. Contact our team today for a chat about how we can help take away the stress of getting things back to normal.

If your drainage system has not been damaged but has failed due to age, some or all the system is likely to need to be replaced. We can still help by referring you to our network of repair and installation partners, so if you’ve noticed your septic tank leaking above ground, call our friendly team today and we’ll ensure help is on its way.

Frequently Asked Questions

What's the first sign a septic tank is leaking above ground?

Usually soggy or smelly ground over the tank or soakaway, sometimes with greyish water pooling. It means the system is overfull or the soakaway has failed, so get it emptied and checked.

Does a leaking septic tank always mean the soakaway has failed?

Not always, but often. If the tank keeps filling and leaking after emptying, the soakaway can't take the water any more. A survey separates a simple full tank from a failed drainage field.

Can an old septic tank be repaired if it's leaking, or is it replacement only?

Age-related failure usually means replacement rather than repair, because there's no single part to fix. Where the leak is a cracked cover or neck, that's different. An inspection confirms it.