Owls Hall, Farm Blackmore End, Braintree, Essex CM7 4DF
01844 877 030



We pride ourselves in being one of the UK’s leading rural wastewater solutions providers. 

Our know-how involves large scale commercial developments and numerous domestic applications, you can rely on our knowledge of legislation and the requirements of the market. Our suppliers have been tried and tested and we always offer sound and independent advice

Sewage treatment FAQs


Why does my septic tank smell?

There may be a few reasons:

  • The vent pipe may be malfunctioning, in which case it may need more detailed inspection.
  • You haven’t been using your toilet or a shower for a while (for instance you went away on long holiday) and the trap dried, which caused the gases to enter the building; the solution is to reintroduce liquid to the system, so just let the water running for some time. If this does not stop the smell, seek further advice.
  • Have you installed a new bathroom in the house recently? Call your plumber to confirm that they have installed a proper trap.
  • Your septic tank is full and needs desludging and emptying. Cal us on 01371 850537 for assistance.
  • Perhaps a vent pipe has been installed too low or too far from the tank; if you suspect this may be the case, contact us for further advice.
  • If the sewage is bubbling up on the surface, it may be a sign the tank or a sewer line is leaking. This problem will not go away, unless the fault part is repaired or replaced. Call us on 01371 850537 for a free assessment and further advice.
  • You have a blocked soakaway

What items shouldn’t be sent to a sewage treatment plant?

  • Motor oil, grease, anti-freeze, brake fluid, etc.
  • Cooking oil and fat.
  • Weed-killers, insecticides, fungicides and other gardening chemicals.
  • Paint, thinners, white spirit, turpentine, creosote, etc.
  • Medicines – all should be taken to your nearest pharmacy for safe disposal.
  • Photographic developing fluids.
  • Nappies (even the disposable ones), sanitary towels, rags, soft toys, tennis balls, etc.
  • Excess amounts of biological detergent and neat disinfectant.

Do I need to top up the bacteria in my system?

There is no real need to top up bacteria in the system – an optimally performing system will have developed all the bacteria it needs and the ecosystem is usually sustainable after 6-8 weeks (depending on the model and weather conditions), however, all systems are ready to use straight after installation. If you are worried about you system and it doesn’t seem to be running as it should, particularly after a harsh winter or an extended period of heavy rain or drought – you may want to check the quality of the effluent to make sure. When in doubt, follow manufacturer’s guidelines in your manual or give us a call on 01371 850537 for free advice.

What quality of water is produced by my treatment plant?

You can describe the quality of water by measuring the amount of Biological Oxygen Demand, Suspended Solids and Ammonia in the fluid. The lower the values are, the higher quality water your system produces.

Sewage treatment plants must reach 20:30:20 to be British Standard approved and to be given the CE mark.  Some of our sewage treatment plants produce better quality effluent and can be further enhanced by the use of soakaways orreed beds.

Please note that septic tanks do no not produce effluent of such quality and require a soakaway for additional filtration.

We size our treatment plants in accordance with the British Water Flows and Loads guidance.

How much power is needed to run a sewage treatment plant?

Values vary between models, however there are plants that operate on the equivalent of a 60 watt lightbulb. Please refer to the manufacturer’s guidelines for details, see our handy sewage treatment plant comparison guide or contact us for more information.

How much does a treatment plant cost to run?

Again, values vary between models – the cheapest model that we supply is the Rewatec Solido and will run on approximately £8-£10 electricity per person per year.  If you have questions about a specific model or want to assess wastewater treatment plant’s cost for your development, contact us for a free site survey.

What would happen to my treatment plant in the case of a power cut?

A power cut should not cause any particular problem, but in all events, check that unit has restarted after a power cut of any length of time and reset the control panel if necessary. If the unit fails to restart then contact our After-Care department.

What is the European Standard and why is this important?

European Standard EN 12566 is a rigorous test for small treatment plants (for building with up to 50 occupants) assessing their efficiency.  Treatment plants should be sized according to the British Water code of practice document on flows and loads.  We use this as the basis for sizing all of our new installations in conjunction with a free site survey.

Since 1st July 2013, it is necessary for all plants sold in the UK to have the EN12566-3 Certificate, otherwise they are deemed illegal and Environment Agency won’t accept them for the Exemption Certificate.

Can I drain rainwater or surface water into my treatment plant?

This is not advisable as excess fluid may influence the sustainability of the system and cause it to overflow. If you are concerned with flooding, you may want to read more about dedicated drainage systems or look into available options of rainwater harvesting systems.

Is it a legal requirement to service my wastewater treatment system?

Yes, as the owner of the wastewater treatment plant, the responsibility of keeping it in order lies with you.  You have a legal xxx But it does not mean you have to perform all the maintenance checks and repairs personally. We offer various service and maintenance contracts, covering all requirements – from periodic checks, through to desludging and any necessary repairs – including a Full Care contract, so contact us for further details.

How often do I need to service my sewage treatment system?

Wastewater treatment plants are designed with the user in mind and are pretty straight forward to use and the maintenance is kept at a minimum. It is a legal requirement that recommended that you service your system at least once a year – even if the desludging period is longer than that (some models provide a 3-year desludging period) – and after spells of unusual weather, i.e. excessive rains, long drought or unusually severe winters. Details vary between models so always refer to the manufacturer’s manual or contact us if you have any questions.

What is included in a sewage treatment plant service?

We service all makes of effluent treatment and sewage systems for both domestic and commercial customers throughout the UK and Europe.

We run a comprehensive list of over 30 checks on your system and carry out any small consumable repair jobs free of charge.

Our service vehicles are fully equipped to carry out all maintenance checks and small repairs; our stock contains a wide selection of spare parts. We act quickly and in most cases can save you the hassle of a second call out.

We always contact you personally before each service or desludging is due. In addition, we have a 24-hour answering service that will usually be answered in person but, if not, will be responded to by 9.00am the next working day.

Do sewage treatment plants need emptying?

Yes, however they work much more efficiently than septic tanks and the desludging periods can be extended to as much a 3 years (depending on the make and model).

Sewage Treatment Installation FAQs


Why should I choose a treatment plant over a septic tank or cesspool?

Advantages of a wastewater treatment plant:

  • Safe effluent: a wastewater treatment plant working optimally produces a much higher quality effluent than that of a septic tank (which often needs additional filtration); plants we supply can discharge fluid of quality as high as 15:25:15 – and this is an exceptional result.
  • Quiet and odourless operation
  • Virtually no impact on the landscape
    of course, there is some excavation to be done, but once the installation is completed, you can hardly notice the plant is under your garden
  • It’s an option preferred by most local councils – it’s deemed a safer and more cost-effective solution, and if councils like it, it streamlines the process of getting building notice
  • Cost-effective: some models electrical running costs are as little as £8-£10 a year
  • It’s a flexible solution: some wastewater treatment plants are designed to grow with your requirements and are capable of handling increasing or fluctuating flow.

How do I install a sewage treatment plant?

Sewage treatment plants need to be installed correctly in order to work correctly, preserve manufacturers warranties and prevent damage to the tank and internal working parts.  For this reason we would always recommend that you choose an experienced sewage treatment plant installer.  We offer a full installation service for all sewage treatment tank models.  We always talk through the details of an installation at the free site survey and also within the paperwork that you will sign, so you will be clear about everything involved.

Once you have chosen the make and model, we will carry out the following steps to ensure that the tank is installed correctly:

  • Arrange for a convenient time to come and install your system
  • Delivery and checks: all our systems are securely packed, delivered in appropriate vehicles and our drivers know how to properly unload the package
  • Excavation: as most units are designed to be located underground we will commence excavation, aiming to cause the least disruption to your garden and the working of your current system.  We have a range of models that can be installed in driveways.
  • Assembly: most of our systems are assembled off site, which makes the installation process quicker.  We will put the tank in place, securing if need be with concrete, we’ll make sure that the internal parts are working and backfill to secure the tank in place.  We’ll also connect the control panel.
  • Connection to electricity supply – if this is available at the time, if not we will be able return to connect.
  • Test and commissioning: once the electricity supply is connected, we will test the system to make sure that it is in full working order and then move to commissioning.  Your comissioning certificate confirms that the system has been installed in line with the manufacturer’s guidelines and will activate any warranties.

If you have any questions, please calls us on 01371 850537 and we can book your free site survey.

What size treatment plant do I need?

That depends on the size of the property and number of its occupants. For example, if you’re managing a holiday let, you are going to face seasonal peaks in demand and the plant needs to cope with periods of increased flow. There are plants suitable for small houses (1-4 bedrooms – up to 6 occupancy), Medium properties (2-6 bedrooms – up to 8 occupancy) and large houses or developments with multiple properties – even commercial ones. It is important to choose the plant fit for the job, that is why we recommend conducting a free site survey to assess your requirements. After that we’ll give you a recommendation and you can make a decision with which option to go for.

We always work within the British Water Flows and Loads code of practice, ensuring that your system is adequately sized to meet your requirements.

Do I need to get planning permission?

You don’t require planning permission for a domestic sewage treatment plant installed below ground.  If you are using the plant for business use or you are interested in installing an above ground tank then speak to us and we will give you more details on the permissions that you will need gain.

Do I need any other permissions to install a tank or plant?

We will apply for a building control notice on your behalf and as standard when we install a sewage treatment plant.  To comply with building regulations the local council will send a representative to sign off the pipework as we work through the installation.  They will check the levels and pressure of the pipework.  The charge for this inspection is set by your local authority, we will pass the fee onto you.  You can choose to pay by cheque which we can pass on, we can add it to your final invoice, or you can page the council directly.  We never add additional charges onto this fee or process.

For most installations you will not require a permit to discharge and you will be exempt from this.  You may choose to register an exemption, which we would recommend should you want to move house in the future as this would be useful paperwork to expedite solicitor activities.  You can find more information on the Government website.

You will need to apply for a permit if you are based in a groundwater source protection zone 1.  You can see whether you are based in one of these areas, by looking at the groundwater map.  The Government has set up the zone system to protect groundwater sources of drinking water, which accounts for about 80% of the drinking water in the UK.

What is discharge?

Discharge, or effluent, is the product of the wastewater treatment system. The aim of a sewage treatment plant is to ensure that the effluent is of a sufficient quality to be disposed of safely.  Wastewater treatment plants produce high quality effluent that is safe to dispose into the waterworks, however septic tank discharge requires further filtration via a soakaway.

Where I can discharge to?

Wastewater treatment plants produce discharge of sufficient quality to be reused or disposed into a ditch or a watercourse. However, if you have a septic tank, you need a soakaway to improve the quality of the effluent.

What is a percolation test and who carries it out?

A percolation test is a way to define how quickly the soil in your area absorbs water to make sure it is permeable enough to absorb and filter effluent before it reaches the ground water . The percolation test is necessary to determine the size of the drainage field or soakaway required for your septic tank.

You can do it yourself, however your local Council may require you to use a qualified engineer, to produce an objective results. It’s best to check with your local authority before performing a test. If you can do it yourself – don’t worry, it is not that complex.

I have a high water table in my area. What can I do?

You need at least 1.2 metres of soil between the soakaway and the water table, otherwise the fluid will not drain away; if you can’t achieve it on your site, all is not lost – you have a few options:

  • Drain the area: you can achieve it with a help of drainage, the job will probably involve gravel-filled trenches and a system of underground drain pipes to secure the soakaway area.
  • Consider alternative wastewater treatment system

All septic tanks need a soakaway, however wastewater treatment plants do not. If a water table is high in your area, you may want to look into this as an alternative solution.

What is commissioning and who does this?

Commissioning is the process of handing the structure over from the constructor to the owner/user; ensuring the product’s safe and reliable performance and ensuring that the warranty is activated.  The process includes: assessment, planning and budgeting, assembly, implementation, quality check and finally sign-off.

We offer a full commissioning for all major manufacturers’ equipment (listed below) and an after sales service involving planned maintenance visits. Please visit our servicing section for more information.

A commissioning certificate will be issued on completion.

Some of the treatment plants that we service: Acorn, Allerton, Balmoral, Bieclere Technlogy, Biodigester, BioPlus, Biotank, Black Hat Systems, Clearwater, Conder, Entec, HD, Hepworth, Klargester, Mantair, Marsh, Rewatec and Titan
Pump Stations: DAB, Grundfos, Klargester, ITT, TT pumps

Pumping Stations FAQs


What is a pumping station and why would I need one?

A pumping station is a way of transporting liquids where gravity cannot cope with the challenge. Usually a pumping station has an overground power supply and a control system and an underground tank and pipework.

You may need one when:

  • Your property is located below the sewer line and you discharge to a mains sewer
  • The effluent needs to be carried up a slope
  • The discharge needs to be carried around an obstacle (a river, a water-reservoir)
  • A cutting-edge architectural design requires a gravity-defying solution.

How often do they switch on and off?

It depends on the level of effluent in the tank; when the amount of fluid in the tank reaches a pre-determined level, the pump switches on. When the amount of fluid drops to the lower limit, it turns itself off again. This is the most cost effective way of operating the system, a sort-of “pay as you go” approach.

What shouldn’t I send through my pumping station?

Avoid following items:

  • Nappies, cotton buds, sanitary towels (even the disposable ones)
  • Excessive amounts of concentrated paints and solvents, etc.
  • Excessive amounts of neat bleach, weed-killers, insecticides, fungicides and other gardening chemicals
  • Motor oil, grease, anti-freeze, brake fluid, etc.
  • Rags, soft toys, tennis balls, etc.

Generally, if you suspect that an item could block a pipe, it’s better to find another safe way of its disposal.

Do pump stations require servicing and maintenance?

Modern systems are designed for low cost maintenance, so under normal exploitation a regular annual service of the chamber and pump is enough to make sure the system operates to its full capacity.  For larger pump stations a 6 monthly service may be necessary.

Stormwater management FAQs


What is rainwater harvesting?

Rainwater harvesting is a way of collecting and storing rainwater with a view of reusing it on your premises. It’s a great strategy of reducing your water bills (by up to 40%) and making sure you have enough water to cultivate your garden, even during periods of severe drought and hose pipe bans. Visit our rainwater harvesting pages to learn more about the models that we offer.

What is a reed bed?

A reed bed is a natural filtration system you can with a view of improving the discharge of your water treatment system. It utilises the ability of a reed to transport oxygen to the soil, hence encouraging microbes to digest the contaminants in the effluent. We offer reed bed installation and maintenance.  Contact us for further details.

What type of drainage system do I need for my home?

Unfortunately, we cannot give you an answer before examining the site. The type of drainage system you require depends on the amount of flooding in your area, type of soil, the size of the building and general design of the property. Contact us for a free site survey and, once it’s completed, we will be able to give you an accurate answer.

How can I deal with flooding on my property?

Unless flooding is a result of a leaky pipework, drainage is usually the cause and we would recommend a variety of drainage systems. There are a number of options to choose from, depending on the size of the property, its location and geological conditions of the area. However, whether you want to save your garden, make more use of patio or deck, or make sure your driveway is not underwater – we can find a solution.

Contact us at Owls Hall: 01371 850 537