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Infiltration Tunnels

A guide to Infiltration Tunnels

A look at Tunnel technology and how it is used. To arrange a free quotation please call us on 0800 3101092 or via our contact form.

What are infiltration tunnels?

At Homeseptic we predominantly use the Infiltration Tunnel 300, designed and manufactured by Graf. The Infiltration Tunnel 300 is designed for the storage and dissipation of storm water. Each Tunnel can store 300 litres of discharge. Once the discharge enters the tunnels it dissipates into the surrounding soil strata in line the relative percolation value (PV).

An infiltration tunnel in use
Infiltration Tunnel 300


Why do we use Infiltration Tunnels?

Because of the infiltration tunnel’s ability to store a large volume of discharge, it enables a far smaller discharge area to be used than a BS Drainage Field. The majority of properties in the UK that have an off mains drainage system do not have sufficient space to install a Drainage field in line with British Standards. Therefore the use of Infiltration Tunnels is a potential solution to the lack of space. For example, a 40m2 Drainage Field is equivalent to a 7m2 Infiltration tunnel Field.

From an environmental perspective, there are also several advantages to other solutions. The tunnels can be installed in the aerobic layer of the soil which facilitates further aerobic digestion. This is the main facet of the justification for the Environment Agency to force people to use Drainage Fields. As the PV regulates the time in this stasis the discharge will have at least as much additional treatment time as with a Drainage Field. In fact, it is likely to have more as the area is smaller with additional storage time.

The tunnels can also optionally have a suck-out point installed which means when they eventually clog up with residual solids they can easily be maintained. In comparison, a far more costly Drainage Field will eventually fail completely due to the build-up of solids.

The Infiltration tunnel can also be used in a driveway, which a Drainage Field cannot. This again gives you far more flexibility.

When do we use Infiltration Tunnels?

We use the Infiltration tunnel in situations where a discharge to the ground is required and a Drainage Field cannot fit in the available space. This is currently the only situation in which the Environment Agency will allow their use. We have only had permits granted for their use with Sewage Treatment Plants.

Frankly, there is no environmental justification for requiring a permit to be used with this type of discharge in combination with a Sewage Treatment Plant. In fact, it causes more environmental damage by the rules actively incentivising Septic Tank and Drainage Field use over it. The difference in the quality of the discharge after tertiary treatment between a Sewage Treatment Plant using an Infiltration Field against a Drainage Field is also at best minimal.

Can you use them with a Septic Tank?

Yes, you can but not without a permit. We have not seen a permit issued for the Infiltration Tunnel to be used with a Septic Tank. If you have had one, please email me.

Why do you need an EA permit for their use with a Sewage Treatment Plant?

Because the EA are more interested in blindly following rules than protecting the environment.

Want to learn more?

We have a large collection of articles containing the answer to all of your questions. Check out our Blog Page 

Our Core Services: The Sewage Treatment expert Installers

On the 1st January 2020, all Septic Tanks that discharge to a Stream, Watercourse or Drainage Ditch will become illegal and will require replacing with a Sewage Treatment Plant. Please see here for more details.

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Expert wastewater treatment engineers who specialise in Septic Tank and Soakaway replacements as well as Sewage Treatment Installations. We are based in the New Forest, Hampshire but operate across the South Coast as well as Wiltshire, Somerset, Devon, Sussex, Surrey, Oxfordshire, and Berkshire.

The Home of Septic tank and private drainage system solutions. 

Based in the New Forest, Hampshire on the border with Dorset and Wiltshire we operate an expert team of off-mains drainage specialists. This encompasses Septic Tank, Soakaway and drainage system problems, installations, blockages, and servicing. In addition, any issues relating to cesspits and sewage treatment plants.

Homeseptic offers high quality, professional advice, repairs and installation for all aspects of effluent cleansing and disposal across the south of England. Whether you’re looking for septic tank installation, sewerage treatment plants or systems, piping or soakaway solutions, Homeseptic employs only the most competent engineers in the drainage and treatment industry and knows exactly which solutions suit each property.

We only install and offer quality systems we believe in, from suppliers we know and trust.

New Forest Philosophy

As we have said Homeseptic is based in the New Forest. A great location in between the cities of Southampton, Salisbury and Bournemouth. We are a group of good friends who grew up together in the area.  Individually we all have grown tired of the way other Drainage firms are run. As a result, this is why we set up Homeseptic. If you want to know more please check out our About Page.

We want to actually put the customer first and turn up to do a great job that we can be proud of. Unfortunately, this is not the case in the market, with most companies pressuring their workers to sell unnecessary works on a visit. Due to this, we offer upfront quotations with any variations discussed before we start work. Our process for a new installation is as follows. A customer gets in contact with us to ask for a quote. we arrange a free quote visit, where you will the engineer who will potentially carry out the work. A quote is issued. If the quote is agreeable we arrange a pre-survey to check the associated pipework and if necessary (hopefully not) a final price is agreed. A deposit invoice is raised and then we organise and arrange for the project to start. 

We are honest hard working professionals, which we hope you will agree with. As a result, it will certainly not turn up in flash sales vehicles and give you a load of chat and then do a terrible job. Our team will come with the job in mind and the aim of giving you the best value we can in order to facilitate a quality installation. 

We cover all of Hampshire, West Sussex, Dorset, Somerset, and Wiltshire. Please get in touch to book a free quote, survey or consultation and see what you think. 

Learn more about Infiltration Tunnels
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Learn more about Infiltration Tunnels
A guide for anyone looking to use Infiltration tunnels instead of a drainage field.
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