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Surface Water and Soakaways


Let us start at the start what is surface water? Surface water is the volume or body of water that is collecting or collected on the surface such as a lake, pond, or river.

What has this got to do with your property? Not every house has a lake, pond or river connected to it but at times it is the victim to rain and storms. These down pours are becoming more advanced when they do finally hit our shores records show that as a country it’s getting wetter during the wetter months. For example, the highest rainfall totals over a five-day period are 4% higher during the most recent decade compared to 1961-1990. The amount of rainfall from extremely wet weather days has increased by 17% when comparing the same time period.

October – January are the wettest months of the year in the UK in Sussex it was recorded in November 2018 rainfall of 133.7mm in the following year November 2019 rainfall of 140.8mm an increase of 7.1mm in a single year.


Attaching to the sewer can only be in place if your local water company allows, in most areas there is not a combined sewer system in place. Due to the new sewers that are being built they are only building to allow the capacity of household waste, not the addition of surface water from properties some areas such as Brighton and Hove have the capacity in parts of the city due to the vast Victorian structured sewers that were built. If you live in the area of a combined sewer you will have to apply for permission to join the sewer system as the capacity of the flows may be at its peak.

The reason why you should not add a surface water line to the main sewer is because it travels a large distance to a sewage treatment works, on this route it may travel to a pump station to be at these pump stations there are holding tanks these tanks fill up then when a level is met the pump will be engaged to move the sewage to the treatment works. If there is an addition to this service in high rain then the pumps may have to work at full capacity in some cases if there are to many additions to this system then the pumps will cut out so that they don’t over run and cause damage to themselves if this happens the well will fill up causing to spill or the sewer will fill up and not empty eventually causing mass flooding and pollutions.

Further down the line at the sewage treatment works there are screens if there is an additional or vast amount of water running into them more than the capacity that they are designed for they will fail leading into the next tank which will distil the operation causing the sewage to not be treated and a pollution.

What has this got to do with your property, how will anyone know? If a local water service is having to deal with excess damage and cost in an area then there will be a cost increase to the water rates, some of the time the water service will also investigate why and where the excess amount is coming from in some cases leading to a fine and also the property having to redirect there surface water, into the correct system so there is an added cost that you have to get someone to install a soakaway.



You can contain your surface water for your property by installing a surface water sewer and running it into a service that is already in use by the local authorities. With their system they run the water into a nearby stream, lake, pond, river or sea. These are a simple affective service that can be maintained by yourself on your own property then it is maintained by the local authority once it has left your property.

If you have a surface water drainage system in your neighbourhood then you can simply install a surface water system for your property and connect to the local system. If this is the case then you will need to check with the authority that owns the system before connecting, with this system the maintenance is low as your responsibility is only on your property once this leaves the property it is the responsibility of the authority who own the surface water line.


The second option is a soakaway previously a soakaway was best described as a pit with rubble inside that your rainwater ran too, with these systems the life span can vary but is on average between 20-30 years before the soakaway is full. These days this type of system is not permitted as they are considered a pollution risk, the system has no filtering design that collects all debris flushed into the soakaway eventually building up with mud and muck causing the soakaway to fail.

PM Drainage installs only the new soakaway systems for both domestic housing and commercial, for the modern fresh start to the way that your property deals with the new extreme weather that the UK has. The

new soakaway is approved both by UK building regulations and Environmental Agencies, you do not require any pre planning approval the local water supplies do not have to be informed there is no hassle with paperwork or waiting.


The new soakaway has been designed to filter the water and as it say soak it away, the design works as a crates/cells installed into the ground wrapped with a membrane then finally laying shingle around both the pipe and the crates/cells. With this system the water will run into the crates/cells self-filtering as it runs both through the shingle and the membrane ones in the crates/cells it will collect there slowly exiting again and soaking into the ground this prevents a vast amount of water collecting in your garden eventually causing damage and flooding. A soakaway should be looked at as an investment as it has a lifespan of about 80 years with no maintenance and no other affects eg damage to your property.

PM Drainage we have years of experience in the drainage industry including working for Southern Water during the time of some of latest storms. We have arrived at scenes where there are a streets under water because the local sewers cannot keep up with the rainfall we have also visited houses and properties in the time that people have needed us to take control, fix the problem and not seen again because we have got the job done. On the other hand we were the crew that had to locate the properties that installed there surface water into a sewer, we were the crew that found who was at fault.

Why wait to be the victim of the next storm why wait for your garden to be underwater? Call PM Drainage today for a quote protect your property.

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