External flooding

Flooding from sewers is distressing and we’re working hard to reduce the risk of it happening. However, it isn’t always possible to prevent it. Find out below what to do if you have sewer flooding outside your property.

Who to contact

  • It’s important to contact your insurer immediately to tell them about any damage the flooding has caused to the outside of your property
  • If you don’t, it may affect any insurance claims you need to make
  • Call our 24-hour emergency number 0330 303 0368
  • Let us know if any nearby properties have been affected so we can help them too.

What we will do

  • Where possible, we’ll attend your property within six hours of you reporting the incident.
  • In the event of widespread storms and flooding, it may take us longer to reach you
  • We’ll call to let you know we’re on our way so please make sure you give us the best number to contact you
  • When we see you, we’ll give you help and advice about what to do next
  • We’ll also ask questions about the flooding to help us understand the cause

What you can do

  • If safe to do so, please take photos of the flooded area as the levels may have subsided by the time we get there
  • Pictures will help us work out why it’s happened and may allow us to consider whether you’re entitled to a payment under our Guaranteed Standards Service
  • Affected fruit and vegetables growing in your garden should be thrown away
  • Keep children and pets away from the flooded areas.

How can you stop this happening again?

Sewers sometimes flood during or after heavy rain if they can’t cope with the amount of water. However, more commonly it’s how we use our sewers and what we put down them that causes problems.

Many incidences of flooding could be avoided by following these tips:

Use containers

Butter tubs, yoghurt pots or jam jars can all be used to collect cooled fat and oil – then just put them in the bin.

Clear your plates

Scrape any leftover food or grease and fat residue from plates, pans or cooking utensils into the bin.

Use a bin

Put a bin in your bathroom for anything that isn’t pee, poo or paper.

Bag it and bin it

Use scented nappy sacks or dog poo bags for any rubbish that may cause a smell.

Compost your food waste

Collect uncooked fruit and vegetable peelings for use as compost in your garden.

Strain it

Use a sink strainer or drain protector to stop hair blocking your drain.

Fat, oil and grease also cause blockages if poured down plugholes as it hardens when it cools.

Worried about contamination of your land?

As most contaminants will be on or near the surface, they’ll be exposed to the sun’s ultra-violet rays which are very effective at killing bacteria. Independent laboratory tests show bacteria should reduce to normal levels as follows:

  • In warm, dry summer weather – nine days
  • During damper, cooler spring/autumn conditions – 20 days
  • In cold, wet weather – 25 days

This can happen for many reasons but the most common is fat that has been put down the kitchen sink or inappropriate items being flushed down the toilet.

Individually, you can make sure that you follow the guidelines in this leaflet. If you are on a shared sewer line, Southern Water can write to your neighbours providing them with the guidelines too.

The crews that attend your property use a small portable jetter that is able to clear most blockages. However, if required, they can also arrange for more powerful equipment to attend.

Groundwater can be a cause of flooding, where underground water reaches the surface and overwhelms drainage networks. Also, flood water can overwhelm the drainage networks as sewers are not designed to carry the additional quantity of flood water. Find out more.

You should call us to investigate the cause of the overflow, it could be a blockage or if it’s raining, water could be entering the sewer system and overwhelming it.

Contact us and we’ll arrange to do a clean up. Find out more about who's responsible for recovery?

If you don’t already know a private contractor who could help, there’s a list of local plumbers on the WaterSafe website at watersafe.org.uk or you can call 0333 207 9030.

This will be to confirm that the blockage has been cleared or if it requires further work.

Guaranteed standards of service payment

If you experienced external flooding caused by a failure of our drainage system, you may claim an amount equivalent to half your annual sewerage charges, from a minimum of £75 to a maximum of £500.

You should complete an application form within three months of the incident. Download the form or you can call 0330 303 0368.

Guaranteed Standards Service payments are not compensation or an admission of liability. 

We’re not able to make payments in the following circumstances:

  • The flooding was caused by you
  • The flooding was caused by exceptional rainfall events
  • If our investigation confirms the flooding was a result of a third party issue. For example surface water running over land, river inundation, private drainage or highway drainage.

 Conditions may apply. See a list of all exceptions.