Septic tanks and sewage treatment plants – what is the difference?

1 Jun 2020


The purpose of septic tanks and sewage treatment plants is to collect water from houses or businesses that are not on mains water supply. The main difference is that a sewage treatment plant actually treats the water, whereas a septic tank just separates the liquid. This means the water that leaves a sewage treatment plant is cleaner. Though you would probably not want to wash in it, it is certainly more environmentally friendly.

 New septic tank regulations

One important point to consider is that in January 2020, new regulations came into effect for septic tanks. These state that if your septic tank discharges directly into surface water, you will be required to update to a sewage treatment plant. This is particularly relevant when selling or buying a property with off mains water supply.

What is the difference between a sewage treatment plant and a septic tank?

A sewage treatment plant has mechanical components that require electricity, whereas a septic tank does not. Septic tanks tend to have two compartments and sewage treatment plants have three. This enables sewage plants to facilitate the treating of the waste it collects, so the water can legally be released to the local watercourse.

How do I maintain my off mains water system?

All off mains water systems require desludging or emptying so they remain functional and maintain the legal quality of water when discharged.  Most sewage treatment plants and septic tanks are recommended to be emptied once per year, though some systems may be more frequent. If you have a small house with single occupancy you may be able to increase to biannual emptying. If you do not empty and service your sewage system regularly, this can cause a build-up of sludge around the components. This can result in the system not working efficiently and the wastewater polluting the location it releases to. It may also cause sewage back up, pools of wastewater in your garden and bad odour which could be a potential health hazard. Regular maintenance will save you money in the long run.

 How do I get my septic tank or sewage treatment plant emptied?

It is recommended to use a professional company that specialises in sewage treatment and drainage to empty your off mains water system. At Owls Hall Environmental, we provide a quick, efficient sewage emptying service at very competitive prices. All emptying and servicing requests are usually carried out within a few working days of customers contacting us. We have over 50 years’ experience within the industry. All our engineers are fully trained and knowledgeable on all types of sewage plants and septic tanks. We are registered wastewater carriers and all waste removed is disposed of in accordance with current legislation.

You can book an off mains water system desludge, empty, service or clean either by completing our online form, emailing or call us 01371 850 537

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