Replacing a Septic Tank with a Sewage Treatment Plant

UK Building Regulations state that all properties, where possible, must be connected to the mains sewer line. This could involve using a pumping station for wastewater removal. If neither of these options is viable, installing a sewage treatment plant or septic tank to handle drainage will be advisable.

Septic tank and sewage treatment plant systems are often treated as the same, but there are a number of differences between the two. If you are thinking of getting a system installed, or considering replacing a septic tank with a sewage treatment plant and would like to know which is actually best, find out everything you need to know below.

Septic Tanks or Sewage Treatment Plants: Which is Best?

The best system for you depends on several factors. These include your personal circumstances, site limitations, necessary permits, and your available budget. These aspects collectively influence which option suits your needs most effectively.

Domestic sewage treatment systems won’t need to be emptied as often and produce cleaner effluent as a result. But it’s also important to remember that they normally cost more to install and will require an electricity supply to operate.

Meanwhile, septic tanks will normally cost less to install, but require more space, need emptying more frequently, and cannot discharge into watercourses.

Pros and Cons of Both Systems

Advantages of septic tanks:

  • Relatively low costs involved in the installation, running, and maintenance
  • They only need emptying once or twice a year at most

Disadvantages of septic tanks:

  • They are only suitable if the ground is porous enough for a soakaway
  • They require the services of a registered waste carrier for emptying – an additional cost to your budget

Advantages of sewage treatment plants:

  • Waste is treated to a higher standard, so what flows out of the tank has a minimal impact on the environment
  • They are the only non-mains drainage system that enables discharge of waste to surface water

Disadvantages of sewage treatment plants:

  • They require an electricity supply to run
  • They require regular maintenance and removal of solid waste by a registered waste carrier

Current Laws and General Binding Rules

Above everything else, it’s important to ensure that the system you decide on is compliant with the general binding rules. All septic tank systems must discharge to ground through a soakaway or drainage field, be replaced by a system that does, or else be replaced by a small sewage treatment system.

Depending on the size of your property and the number of occupants, it may be more practical to replace a septic tank with a treatment plant rather than dig up the entire exterior to put down a drainage field.

Other Things to Remember

Alongside laws and regulations, there are a number of other things you will need to think about and remember when deciding on a system:

  • The property owner is legally responsible for waste management. If you do not prevent waste from polluting, you will be at risk of prosecution.
  • Always check the suitability of your property’s ground before fully committing to a system.
  • Septic tank soakaways can still pollute groundwater with effluent if they are installed incorrectly or in the wrong location; site surveys are crucial in preventing this.
  • You must first apply to and register with the Environment Agency if you are intending to discharge a sewage treatment plant into a watercourse.
  • There is no need to register a septic tank in England (though there is in Scotland, Wales, and Northern Ireland), but you should still keep records of maintenance and notify the Environment Agency if discharge ceases.
  • If informed that you do not require a permit, you will still have to comply with industry guidelines on the installation of septic tanks and sewage treatment plants, as well as achieve compliance with Building Regulations or BS 6297 regarding soakaway design. You will also have to comply with British Water’s advice regarding de-sludging and servicing.

Should I Replace My Septic Tank?

You will not have to replace a septic tank with a sewage treatment plant if it meets all general binding rules and legal requirements. However, if you can afford to install a sewage treatment plant, you will find a wide range of benefits for your property and the local environment. It will also guarantee full peace of mind if you’re unsure whether your ground is suitable enough for draining wastewater.

When in doubt, it is always best to seek the advice of a professional drainage engineer.

Our Septic Tank Services

Leveraging years of expertise, we keep systems across South East England and South London compliant with all general binding rules. We specialise in identifying and fixing issues promptly, restoring your tanks to optimal performance. Commit to our regular maintenance service and enjoy a long-lasting, impeccably functioning tank. Trust BlockBusters to keep your systems consistently at their peak.

Get a Free Upgrade to a New System

If you have a septic tank system in need of extensive repairs, you can always get it replaced with a sewage treatment plant, for free, through us. This is covered by your insurers, so if you want to save thousands of pounds on a property essential, contact us to find out more.

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