Understanding Foul Water Drainage Regulations and Services

Your property will produce two types of water that require drainage: surface water and foul water. These two types of water are not handled in the same way in your drainage system, and in fact, have different rules and regulations surrounding them. 

Here, we’ve provided an explanation of each, why surface water and foul water shouldn’t mix in your drainage system and a quick explanation of the regulations surrounding a property’s drainage system.If you think you have an emergency with your foul water drainage, just get in contact with our team, who are available 24/7, for a free call out now. Our drainage engineers are highly trained and very experienced and provide quick, reliable service.

What is the Difference Between Foul Water Drainage and Surface Water Drainage?

What is Foul Water Drainage?

Foul drainage refers to the pipework system that carries away wastewater from the bathroom, kitchen and utility room. The appliances and systems in your property that produce foul water include:

  • Toilets
  • Sinks
  • Showers and baths
  • Washing machine and dryers
  • Dishwashers

This water is considered ‘foul’ because it is contaminated with pollutants, like human waste and harmful chemicals. Usually, this wastewater will be directed through the main sewer system along to a sewage treatment plant.

In homes that are not connected to public sewers, foul water drainage pipes will discharge into private sewer systems like cesspits or septic tanks. It’s important to note that the Environment Agency requires registration of septic tanks, sewage treatment plants and cesspits. Read more about that here.

If you’re confused about terminology, it’s thankfully fairly simple. In general, any pipes that are underground will be referred to as foul drains or foul sewers while pipes above ground are usually referred to as sanitary pipework. 

What is Surface Water Drainage?

Surface water refers to the excess water from rain that your property collects. Rainwater can drain naturally into the ground in rural areas. But in urban areas, it’s usually collected by drains since there isn’t as much space or natural land for the rain to soak into. In this case, the water collected in these drains is then channelled to natural watercourses like rivers and streams.

Surface water doesn’t need to be handled or cleaned by treatment plants as it hasn’t become contaminated by use in your property. It’s safe for surface water to be directed into soakaway drains. We have an excellent guide to rainwater soakaways, including how to build one in your own garden if you find you suffer the effects of excess rainwater.

Keep Foul Water Drainage and Surface Water Drainage Separate

It’s very important to keep the two water drainage systems separate to ensure the health and safety of the water system. If foul water is directed into surface water drains, any local watercourse that it then discharges into will be polluted with the contaminated water.

There can also be negative effects from surface water entering foul water drains. When excess surface water enters these drains, the system can be overwhelmed and the drainage pipes can back up and flood. 

Can You Have Combined Foul Water and Surface Water Drainage?

Unfortunately, older properties often have combined drainage systems, meaning the surface water and foul water are collected in the same sewer. Sometimes, when disruptive building works have taken place on a property, a misconnection can occur which send your drains and sewers to the wrong mains.

You can only have a combined foul water and surface water drainage system under exceptional circumstances. Read the building regulations section below to find out more.

Is My Property Connected to Foul Water Drainage?

CCTV Drain Survey

If you’re not sure or if you suspect that the foul water drainage pipes of your house are not connected correctly, it’s best to get a professional in to map out your full drainage system. We can help with this. We provide free CCTV drain surveys where we push a high-tech camera through your pipes and inspect the entirety of your system to find any flaws. This is the safest way to identify any issues. We then provide free, no-obligation diagnoses and quotes on any repair work needed. Contact us to find out more. 

Building Regulations for Foul Water Drainage 

The Building Regulations set out by the document has an order of priority list detailing where the foul water of a property should be discharged:

  1. A public sewer
  2. A private sewer system communicating with a public sewer
  3. A septic tank or other wastewater treatment plant
  4. A cesspit

What this means is that you need to attempt to connect your foul water system in the above order. It is only possible to have approved combined foul and surface water drainage systems if you’ve exhausted these options. You will need evidence in the form of:

  • A ground investigation report
  • Percolation test results
  • Written evidence from building control

How We Can Help With Foul Water Drainage

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Foul water drainage regulations can be confusing to understand on your own. If all of this is a little overwhelming or if you’re not quite sure what your local authority needs, get in touch with our team of experts. We offer free advice that comes blacked by decades of experience with all drainage problems.

If you’re planning extensive building work, are worried about your foul water drainage or surface water drainage, or if you have any concerns about your drainage system as a whole, we’re happy to help.

Our professional drain inspections are free of charge and can help you with a range of drainage problems. Just contact us today to find out how our team of highly skilled drainage engineers can help you.

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