Important Information from our suppliers

Things you need to know before updating your system.

Septic Tanks

Installation, Replacement or Repairs to Septic Tanks

If the septic tank and soakaway was installed more than 15 years ago, then you do not need permission to replace or modify your septic tank or soakaway.

The Environmental Agency and UK Building Regulations class any work to update, repair or replace an existing septic tank or soakaway as a 'modification'.

However any work carried out by yourself or a contractor must be done responsibly, and must not pose a pollution risk to the surrounding environment or any water courses.

- Septic Tanks should be sited at least 7m from any habitable parts of buildings, and preferably downslope.

- Where septic tanks are to be emptied using a tanker, the septic tank should be sited within 30m of a vehicle access provided that the invert level of the septic tank is no more than 3m below the level of the vehicle access. This distance may need to be reduced where the depth to the invert of the tank is more than 3m. There should also be a clear route for the hose, in order for the tank to be emptied and cleaned without hazard to the building occupants and without the contents being taken through a dwelling or place of work.

If the septic tank or soakaway was installed less than 15 years ago, you will need to contact HM Government, Building Regulations.

- Septic tanks should have a capacity below the level of the inlet of at least 2,700L for up to 4 users in a domestic property that is a permanent residence. The size should be increased by 180L for each additional user. Please take note that this does not apply to temporary dwellings such as mobile homes, stable blocks, caravans, granny annexes etc.

- Factory made septic tanks are available in glass reinforced plastics, polyethylene or steel and should meet the requirements of BS EN 12566-1. Particular care is necessary to ensure the stability of these tanks.

-The inlet and outleft pipes of a septic tank should be provided with access for sampling and inspection.

Septic Tank Notice

By law if you own any kind of sewage system, then you are required to display a notice in your home. The information on the notice should give details of the nature and frequency of any maintenance you carry out on your septic tanks, cesspool or wastewater treatment system.

If your property has 4 or more bedrooms

If your property has 4 or more bedrooms and conforms to the following requirements:

  • If a property discharges more than 2,000L of sewage effluent a day.
  • Your property discharges into the ground through a drainage field, (also called a soakaway or infiltration system)

Then by law you must apply for a septic tank permit. To work this out - according to British Water, each person produces around 280L of wastewater per day. The Environmental Agency Services states: You must allow for 2 people per bedroom.

This law applies even if you only have 1 or 2 people lving in the dwelling, as the size of the sewage system must be based on the number of bedrooms.

Septic Tank Maintenance

Septic tanks must provide suitable conditions for the settlement, storage and partial decomposition of solids. The solid waste (sludge) also needs to be removed at regular intervals.

Most people organise their systems to be emptied once or twice a year.

Many people also use septic tank soakaway worms as a way to break down and eat the sludge.

Soakaways

Every septic tank has a soakaway attached. A soakaway allows the wastewater that is discharged from the septic tank todrain and soak away naturally into the soil.

Overtime however the septic tank soakaway can become blocked or clogged up with grease and fat.

Typical sympoms of this are: Having to empty the tank frequently, soggy patches of wastewater collecting in the lawn, bad smells etc.

Once the soakway is blocked, having it jetted will not help, it cannot be unblocked. There are two directions to go in:

1. Replace your soakaway

2. Use soakaway worms

Percolation Test

Do I need to carry out a percolation test?

If you are contsructing the soakaway in the topsoil, then No. Topsoil is defined as the upper, outermost layer of soil. The depth of top soil varies and can typically be between 6-35 inches in depth. It offers the best protection in the world as it has the highest concentration of bacteria, micro organisms and organic matter for biological activity.

Water and wastewater makes its way from the topsiol into ditches, streams, rivers and seas.

In some cases however ground conditions may not be favourable, such as your property maybe situated in a hollow, valley or flood plain. In this instance a percolation may be reccomended.

-It is important that the percolation charecteristics are suitable in both summer and winter conditions.

-Top soil meets these requirements

However if you are constructing your soakaway in poorly drained or saturated subsoils such as clay then:

- A preliminary assessment should be carried out, this is called a percolation test.

Please follow these instructions on how to carry out the test:

- A hole 300mm square should be excavated to a depth 300mm below the proposed invert level of the effluent distribution pipe. Where deep drains are necessary the hole should conform to this shape at the bottom, but may be enlarged above the 300mm level to enable safe excavation to be carried out. Where deep excavations are necessary a modified test procedure may be adopted using a 300mm earth auger. Bore the test hole vertically to the appropriate depth taking care to remove all loose debris.

- Fill the 300mm square section of the hole with water to a depth of at least 300mm and observe the time in seconds, for the water to seep away from 75% full to 25% full level (i.e a depth of 150mm). Divide this time by 150. The answer gives the average time in seconds (Vp) required for the water to drop 1mm.

- The test should be carried out at least three times with at least two trial holes. The average figure from the tests should be taken. The test should not be carried out during abnormal weather conditions such as heavy rain, frost or drought.

- Drainage field disposal should only be used when percolation tests indicate average values of Vp of between 12 and 100 and the preliminary site assessment report and trail hole tests have been favourable. This minimum value ensures that untreated effluent cannot percolate too rapidly into groundwater. Where Vp is outside these limits effective treatment is unlikely to take place in a drainage field. However, provided that an alternative form of secondary treatment is provided to treat the effluent from the septic tanks, it may still be possible to discharge the treated effluent to a soakaway.

Polybed Soakaway Pipes

Do i need to contact Building Conrtol or the Environmental Acency before I install, repair or replace the septic tank or soakaway?

Not if the septic tank and soakaway was installed more than 15 years ago.

The Environmental Agency and UK Building Regulations class any work to update, repair or replace and existing septic tank or soakaway as a 'modification', and can be replaced like for like. However any work carried out by yourself or a contractor must be done responsibly, and must not pose a pollution risk to the surrounding environment or any water courses.

If the septic tank or soakaway was installed less than 15 years ago then any work carried out has to be compliant with certain requirements as set out in section H of the current Building Regulations.

Soakaway Crates

Do i need to contact Building Conrtol or the Environmental Acency before I install, repair or replace the septic tank or soakaway?

Not if the septic tank and soakaway was installed more than 15 years ago.

The Environmental Agency and UK Building Regulations class any work to update, repair or replace and existing septic tank or soakaway as a 'modification', and can be replaced like for like. However any work carried out by yourself or a contractor must be done responsibly, and must not pose a pollution risk to the surrounding environment or any water courses.

If the septic tank or soakaway was installed less than 15 years ago then any work carried out has to be compliant with certain requirements as set out in section H of the current Building Regulations.

Are Soakaway crates approved by Building Regs?

Yes.

"Soakaways can consist of different materials, as long as biological treatment takes place in the soil"

"Soakaways should be designed and constructed to ensure aerobic contact between the liquid effluent and the subsoil"

Soakaways crates that are installed in the topsoil legally meet this requirement.

All soakaway crates conform to Section H of the UK Building Regulations.

In some cases however, ground conditions may not be favourable, such as your property may be situated in a hollow, valley or flood plain. In this instance a percolation may be reccomended.

Why do some websites say soakaway crates are not approved?

- We find that some companies have an agenda to sell you their products based on misinformation and scare tactics.

- Others we find are well meaning, but are just not up to date with current building regulations, methods and products.

- Section H of the UK Building regulations is the authority on septic tank and soakaway construction and installation.

Siting of Soakaway

What is the law regarding the siting of a septic tank soakaway?

  • A drainage field or mound serving a wastewater treatment plant or septic tank should be located:
  • At least 10m from any watercourse or permeable drain
  • At least 50m from the point of abstraction of any groundwater supply and not in any Zone 1 groundwater protection zone
  • At least 15m from any building
  • Sufficiently far from any other drainage fields, drainage mounds or soakaways so that the overall soakage capacity of the ground is not exceeded.
  • Disposal area should be downslope of groundwater sources.
  • No water supply pipes or underground services other than those required by the disposal area.
  • No access roads, driveways or paved areas should be located within the disposal area.
Tags: empty, carried, water, property, plant, grease, building, maintenance, soakaway, treatment, sewage, septic, percolation
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Bates Environmental Ltd

58-64 Station Street
Donington
SPALDING
Lincolnshire
PE11 4UJ

Tel: 0800 043-37-11
Fax: 01775 822-983

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