Sewer blockages and flooding
Our team of sewage inspectors work to help keep our sewerage network clear. But sometimes blockages occur and can stop, or reduce, the flow of sewage through sewer pipes.
Identifying blockages
Here are some signs you have a blockage :
- Bad odour around the property
- Water or waste that’s slow to drain or not draining, including plug holes
- Manhole(s) outside the property surcharging
What to do next if you have a blockage
We need to establish who is responsible for what pipework as internal pipework is the responsibility of the homeowner. Please watch our 2-minute video below and diagram to determine responsibility.
If the pipework belongs to you, you will need to contact a plumber.
If the blockage is caused by a public sewer, please call us as soon as possible on 0800 085 3968. One of our team will call you back within the hour to inform you when we will be attending, you will also be given a named contact who will be your case manager during the incident.
We’ll always respond to blockages. We aim to get to you within 24 hours, sometimes, especially during severe weather, we may take a little longer, but we’ll keep you informed of our likely time of arrival.
When we attend if the blockage is caused by a public sewer, we will clear it free of charge, if it’s on your private pipework, we may be able to clear but there will be a charge. Our jetting operator will talk you through this during their visit. Our charge for clearing a private blockage including VAT is £165.58.
Internal Flooding
What we will do
If the flooding is caused by a public sewer, please call us as soon as possible on 0800 085 3968. One of our team will aim to contact you within the hour to inform you when we will be attending, you will also be given a named contact who will be your case manager during the incident.
We’ll always respond to sewage flooding incidents. We’ll aim to get to you within 2 hours, day, or night. Sometimes, especially during severe weather, we may take a little longer, but we’ll keep you informed of our likely time of arrival.
What you need to do
Contact your insurance company straight away to tell them about the flooding and any damage caused. They will be able to help you with arranging the clean-up and drying of your property, finding alternative accommodation if needed, and give you advice and support on making a claim for damages or losses.
Once we establish the cause of the flooding, we will remove sewerage debris and disinfect where we can, we will hopefully do this the same day, during busy periods this may be the next day.
External Flooding
What we will do
If the flooding is caused by a public sewer, please call us as soon as possible on 0800 085 3968. One of our team will call you back within the hour to inform you when we will be attending, you will also be given a named contact who will be your case manager during the incident.
We’ll aim to get to you within 4 hours. Sometimes, especially during severe weather, we may take a little longer, but we’ll keep you informed of our likely time of arrival.
Once the cause of the flooding has been stopped, we’ll clear all sewage debris from affected areas. We’ll treat any flooded areas with disinfectant. Please note, we can only clean underneath decking if it’s been lifted for us in advance.
What you need to do
If there is damage to your garden, e.g., lawn, chippings etc, please contact your home insurance company who can give you advice and support on making a claim for damages or losses.
You will need to restrict the use of the affected areas until this work is done. Water industry guidelines advise that the garden will be safe after a clean-up and quarantine period, as follows:
Season |
Turf/Clay |
Soil/Sand/Shingle/Bark |
| Spring | 13 days | 20 days |
| Summer | 6 days | 9 days |
| Autumn | 13 days | 20 days |
| Winter | 18 days | 11 days |
What happens next
What we will do
We investigate every case of sewer flooding. A member of the Welsh Water team will meet you and we’ll do all we can to understand why the flooding happened.
We’ll carry out a full investigation, including a CCTV survey of the sewer, to help establish the cause of the flooding.
If you are flooded by one of our sewers, you will be entitled to a payment through our Guaranteed Standards of Service (GSS), in line with industry regulations. You will also receive £100 goodwill gesture payment if your home has been flooded you will receive this payment within 7 days.
GSS payment values
Internal sewage flooding: If you have suffered internal sewage flooding from our sewers (when sewage enters a building or your home or integral garage), we’ll give you a payment equivalent to your annual sewerage bill (a minimum of £150 and a maximum of £1000 per incident) within 20 working days.
Serious external sewage flooding: If sewage enters your land or property preventing you from accessing your home; causes your garden to be extensively flooded, effectively leading to its destruction; or your outbuildings/non-integral garages being flooded from our sewers, we’ll give you a payment equivalent to half of your annual sewerage bill (a minimum of £75 and a maximum of £500 per incident) within 20 working days.