Skip navigation

Help & Advice

Site Assessment

Below is an explanation of any jargon used on the web site, also there are some common problem areas explained. If you have any further queries regarding any of the below please don’t hesitate to phone or e-mail us. Please also be aware of our Help & Advice Disclaimer.

Site Assessment and System Selection Questionnaire

PDFWhich product do I need? (Off-mains)

Backed up drains or tanks

Some people experience problems where their drains or tanks have backed up after a rain fall. A number of steps can be taken to help identify the problem:

1. When the tank is emptied by the de-sludging vehicle sometimes you can see the water running backwards from the exit pipe of the last tank, because it is under water. This confirms that the exit pipe is the problem area and a suitable solution can be provided by either a pumping station with new soakaway (subject to suitable Percolation test results) or a treatment plant with pumping station if you need to discharge to the water course (ditch, stream, river, canal, lake, lock or pond).

2. If the tank itself is porous and is leaking the check for this is to have a long dip stick (a piece of wood) and once the tank has been emptied take a measurement and mark the level on the dip stick. Make sure no water is running from the property or buildings and return a few hours or the following morning and retake the level on the dip stick. If no discharge has entered the tank from the property or buildings then the level on the dip stick should not have moved from your previous reading. If there is movement on the dip stick, this indicates the ground water level on the outside of the tank is higher than the inside of the tank since water always finds its own level due to equal pressure on both sides of the tank. The usual solution for this is a treatment plant with a pumping station. If the ground water is so high that the tank is filling with ground water these conditions are not suitable for a septic tank and soakaway /drainage field.

Options;

  1. We can arrange to have the soakaway Jet Washed to see if there is a blockage and hopefully provide some more information of the current condition of the soakaway.
  2. Please read Introduction to Percolation / Porosity Tests
  3. Installation of a new effluent system, which is suitable for the property and complies with the current legislation.
  4. We do have submersible pumps with or without above ground storage tanks for hire to help maintain the effluent system while a longer term solution is decided upon.

Top

Building Notices

The works usually fall into schedule three of the building notice which is controlled by your local Council.

Cesspool

This is a sealed tank and every thing that enters it has to be taken away by a tanker. The size of the tank for a property is regulated by the Building Inspector at local Council. For a single dwelling 18180 litres (4000 gallons) is the minimum allowable capacity suitable for two residents only. This size should be increased by 6,800 litres for each additional user.

Consent from the environment agency

This is the consent to discharge licence issued by the Environment Agency. This licence is needed to allow you to discharge the treated effluent from a treatment plant.

Discharge

This is the liquid / fluid that leaves the equipment / machines we install

Top

Drainage Mound

This is a mound of earth that may already be present or is created to support a Soak away / Drainage Field to allow the effluent to be dispersed onto the property. This system is usually required where the water table is high in the ground or the soil in the ground is not very suitable for a Soak away / Drainage Field. By using a drainage mound the soil may be better quality for drainage which a Percolation Test / Porosity test would show.

Environment Agency Requirements

These are requirements set by the Environment Agency that apply to most installations. If a drainage scheme does not comply with these requirements it is considered to be illegal. The Environmental officer would determine these requirements through a site visit and inform you accordingly.

Apply for a discharge consent

Effluent

This is the liquid / fluid we describe as treated effluent that is usually directed to a ditch or soakaway / drainage field.

Effluent Pumps

These are pumps used for pumping the effluent, which is usually from a treatment plant where gravity discharge is not possible

Top

Flow rates

This is the rate of flow and is usually expressed in litres per second or minute

Gravity Discharge

This is where the liquid leaving the equipment or machine can flow down hill by gravity.

Groundwater

This is water present in the ground; this water level fluctuates between winter and summer depending on the volume of rain that is received.

Invert Level

This is the measurement from ground level to the bottom of the inlet pipe of the effluent system.

Main Sewer

This is where the mains water supplier takes your sewage for you and treats it at the sewage works.

On site dangers

These are dangers that could cause possible harm to all personal or animals.

Top

Percolation / Porosity Test Procedure

This is the process used to evaluate if the ground is suitable for a soakaway/drainage field system. By carrying out trial inspection holes you are trying to duplicate the way the soakaway/drainage mound would operate under working conditions before incurring any expenses to see if there is a chance of it working successfully. The test results will differ enormously from the drier to wetter months. Most systems if they are going to fail are in the wetter months where the ground is saturated, which means a soakaway is the not the correct system for the property.

Most people think since it has worked for the last fifty years it should continue for another fifty years. However other points need to be considered. When the original system was installed it is likely there were not washing machines or dishwashers using detergents. The volume of water leaving the property has increased. Ditches are not cleaned out as much now, since there are less people working on the land and this causes the ditches to stay artificially high. The most important change is that regulations are so much tighter now and are still becoming tighter. A soakaway/drainage field must be 10 metres from a water course and ideally 10-15 metres from a habitable building. The system must also be 1 metre above the water table level even in the winter months. With all the different points taken into consideration it usually makes more sense to install a treatment plant if possible and have a system that is sized according to the type and volume of liquid leaving the property and be legal at the same time. This also helps when the property is placed on the market for sale since the potential buyers look closely for problems and if they are being deceived through the legal declaration form then potential legal action may result.

If you required a quotation for the installation of a new soakaway, we would require the results of the percolation tests sent to us. Please note any soakaway installed will be based on the test results provided and this should be taken into consideration for a long term decision on the best way forward.

If you would like us to visit your property to discuss the possibility of a treatment plant system and take the correct information to be able to provide you with a quotation then please contact us.

PDFTDS0005-07 Subsurface Irrigation Systems

Top

Sample Chamber

Where a sample point is not accessible at the property a sample chamber is used to retain a volume of the treated effluent prior to entering the watercourse.

Sample Point

This is the location identified on the Environment Agency consent to discharge where a sample can be taken of the treated effluent prior to entering the watercourse.

Sewage Treatment Plant

This is a machine that requires electricity to treat raw sewage into a treated effluent which is allowed with consent from the Environment Agency to enter a water course. This is ideal for properties without suitable room or conditions for a drainage field / soakaway.

PDFTDS0001-03 How to keep your sewage treatment plant running sweetly

Top

Septic Tank

A septic tank is different to a treatment plant in that there is no treatment process and therefore the discharge into a water course is illegal. (Below is a link to our septic tank operational guide as well as the septic tank smell problem help file.)

Smell

Some people experience problems with smells at their property. It can be quite difficult to determine the cause and source of a smell problem. A number of steps can be taken to help identify the problem:

1. Has the effluent system been emptied in the last twelve months? If not we would suggest you carry this out first and then evaluate the smell problem over the next couple of weeks after emptying with the steps below.

2. Try and establish if the smell is stronger towards the effluent system and even strongest at the system itself.  If this is the case then the problem is the effluent system, which we can advise you further on your existing one or a replacement one.

3. If the smell is not in the vicinity of the effluent system and thus not the cause of the smell, we suggest you view your inspection chambers prior to the effluent system to see if they are blocked at all, if not then it is likely the pipes joining them are also in working order. If they are blocked then please contact regarding having the pipes jet washed.

4. Once the steps above have been completed with your existing system you have proven that the effluent system is not likely to be the cause of the smell problem you are experiencing. This would then indicate a possible venting or a stack pipe problem at the property itself, which a local builder should be contacted to investigate the problem further for you.

Top

Soak away / Drainage Field

This is the process used to disperse the untreated effluent from a septic tank or treated effluent from a treatment plant where a ditch is not available into the ground. For the size and construction of the soakaway / drainage field this is determined by carrying out a Percolation Test / Porosity test

Top

Storm Water

Storm water should not enter an effluent system, since this dilutes the bacteria and will potentially create an illegal discharge to the water course. Where connection to mains drainage is being considered this is also a requirement of the Water Companies that the Storm water is excluded from the foul system.

Storm water could be water from the roof that enters the foul drain system through your roof down pipes or from yard gullies. To help establish if your property’s foul system does receive storm water the following method may be of help.

The test for this is to run a hose pipe into the down pipe or yard gully when it is not raining and there is no water running inside the house or any other buildings and see if this water is passing through the inspection chamber prior to the septic tank. It may also be helpful to check the inspection chamber prior to the septic tank when there is a heavy rain with no water running in the house or buildings and this may show if any water is entering the system or if any pipes are cracked where water may be seeping into the foul pipe system.

If you discover storm water is entering into the foul system make a plan of your property and identify the areas that need redirecting. We are able to provide a quotation for the redirecting works if you are unable to carry these out yourself. If you have difficulty in establishing the layout of the drains, we are able to provide engineers who would use drain dye to help establish the path (an outside working water tap would need to be provided free of charge). The engineers also carry a Cat and Genny system with a sonde. The sonde is shaped like a mole and it can be passed through the drains sending a signal to the receiver above ground providing approximate depth and location. If you do require the assistance of the engineers, please contact us and we can provide our current charges for this.

If you have any queries or require further assistance, please do not hesitate to contact us at anytime.

Top

Watercourse

This is the expression used by the Environment Agency which could be for a ditch, stream, river, canal, lake, lock or pond

Wet and Dry site

A wet site is where groundwater lies above the base of excavation at any time where as on a dry site the groundwater is below the base of excavation. Some sites maybe, at the time of the work being carried out, dry sites. However any changes in the water table will turn it in to a wet site thus causing many problems. We carry out all our installations as wet sites which therefore protect the systems against seasonal changes in the groundwater levels.

Top

Step 1 - Consultation and visual inspection

Make an initial visual assessment of the land's suitability for septic tank drainage:

  1. Consult the Environmental Regulator and other sources of local knowledge.
  2. The drainage field should be sited on land sloping away from the property.
  3. There should be adequate access for desludging vehicles.
  4. Any stream, well, borehole or spring on-site can affect the positioning of the unit.
  5. The site area and proximity of the site boundaries will help determine whether an adequate drainage field can be installed.
  6. Water loving plant species could indicate poor drainage.

Step 2 - The trial hole

If the results in Step 1 are satisfactory, further investigations can take place which involve breaking the ground:

  1. Well drained soil is usually brown, reddish or yellow. Grey or blue subsoil often means heavy clay or poor drainage.
  2. The position of the water table must not rise to within 1 metre of the effluent distribution trench.
  3. There should be at least 0.5 metre of suitable subsoil available below the base of the distribution trench.

Step 3 - Percolation testing

If Steps 1 and 2 are favourable, it is essential that you carry out a percolation test in accordance with BS 6297 and building regulations. The percolation test will indicate soil porosity values. Excessively rapid percolation can threaten groundwater resources, whilst very slow percolation can result in surface ponding. Percolation test results will help you decide on the area of land needed to provide a sustainable drainage field.

2000 Building Regulations Part H2 now provide new guidelines on percolation testing which indicate that the test has to succeed within certain criteria. Even when tests fall outside this criteria, treatment plant may be an acceptable option.

Top

HELP & ADVICE DISCLAIMER: "We have compiled this information after years of experience in drainage. However if you are in any doubt about carrying out any of the suggestions above please call us as we cannot be held responsible for any possible problems caused by the solutions offered above."