Identifying Drainage Systems

Garden drainage problems

Many people aren’t aware or interested in the type of drainage system serving their property, until something goes wrong. Let us help you with identifying your garden drainage problems by analysing your drainage systems. If you live in a rural area your property may have its own drainage system, rather than being connected to a main sewer.  This system may serve just your property, or you may share it with one or more of your neighbours.

Septic tanks, cesspits and sewage treatment plants – If you live in a house that’s not near a main sewer, your property will be connected to one of these types of drainage systems.

If you would like advice on resolving your garden drainage problems please contact us, we cover Lincolnshire, Nottinghamshire and Yorkshire

Which drainage system does my property have?

These are the three main types of off-main drainage systems in use across the UK. Two of these are common – septic tanks and sewage treatment plants. One increasingly less common – cesspits. All three systems are discussed in more detail below.

Garden Drainage Problems In Lincolnshire | Croft Drainage Solutions

Typical septic tank layout

Septic tanks are often found in rural areas and their problems can be costly and complicated to fix.  Many people believe that their drainage system is a septic tank when in actual fact it may be a cesspit or sewage treatment plant.  Why choose us? Croft Drainage Solutions have the experience to identify and understand the type of drainage system serving your property, the problems affecting it and, in turn, what work needs to take place to correct the problems. Often the cost to fix a septic tank or sewage treatment plant problem is covered by the property owners existing insurance policies.

We can advise you if this may be the case and handle the claim and rectification works. For more information see ‘Am I Insured’.

Septic tanks

Septic tanks are still the most common type of off-mains drainage system. They have been widely installed for many years. It is a simple system – a pipe runs from your property to the septic tank. Here the waste separates into solids and liquids. A baffle retains the solids and allows the partially treated effluent to move into the drainage field. Here further treatment takes place and the effluent disperses into the ground.

In older systems the septic tank sometimes runs into a soakaway or watercourse. These types of systems no longer meet environmental requirements. See our Drainage Regulations – ‘A Quick Guide Section’ for more information.

Your property may have a septic tank if you can:

  • See 2 to 4 manholes or other covers in a small area (see picture below)
  •  Vent pipes may also be visible above ground – grey pipes in picture below
Identifying Drainage Systems - Septic Tank Pipes | Croft Drainage Solutions

Septic tank with vents visible

Note there will not be an electrical supply to the septic tank or the sound of machinery running. If this is the case, you are likely to have a sewage treatment plant.

Sewage treatment plants

A sewage treatment plant provides a greater level of treatment to your property’s waste than a septic tank.  In most cases the effluent produced goes directly to groundwater or a watercourse. An electrical power supply powers internal components, pumps air into the system and sometimes pumps the discharge out of the treatment plant.

There will typically be a box mounted externally near the treatment plant, this will emit a constant low level humming noise – this is normal. The more modern installations contain a visible and audible alarm on the treatment plant. Indicating the plant requires attention.

Identifying a sewage treatment plant

Blower box for sewage treatment plant

There is normally only a single, large cover for the sewage treatment plant (see picture below).

Sewage treatment plant lid

Typical sewage treatment plant cover

If you would like advice on your system please contact us. we cover Lincolnshire, Nottinghamshire and Yorkshire.


No longer installed in Scotland they are the usually the ‘last resort’ in the rest of the UK. The reason for this is that a cesspit is just a holding tank for all the waste that leaves your property. No treatment takes place so if a leak occurs it can cause significant pollution. They need to be large enough to hold all the waste produced by the house and need emptying frequently. Thus they are costly to install and maintain.

Yet there are still many older ones around. Due to their size there is often a visible concrete slab with a single manhole in it. This is the simplest way to spot if you have a cesspit. Note we do come across properties where the owner thinks they have a septic tank but it is in fact a cesspit.

For any advice on your cesspit please contact us, we cover Lincolnshire, Nottinghamshire and Yorkshire.