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Common problems with septic tanks

A properly-maintained septic tank should give a long lifespan and few problems, but the age of the vessel, the construction of the attached drainage field and the maintenance history (or lack thereof!) can all contribute to a potentially-costly replacement needing to be installed.

Older septic tanks without a drainage field (soakaway) attached are no longer legal under current legislation and will need to be replaced with a sewage treatment system or new septic tank with soakaway.

If your septic tank is giving off a foul odour, or you are noticing odours coming from toilets and sinks, this may indicate poor ventilation. Check that the system is ventilated correctly through the stench pipe on the property/remote vent.

The septic tank may also require emptying – if the primary tank is not emptied as recommended, this can cause odours.

Drainage field failed
The most common problem with a drainage field is backing-up of sewage into toilets/sinks. This can be identified by checking the levels in the septic tank. The cause is likely to be a failed drainage field, which could be fully saturated due to poor soil conditions or a high winter water table, or a blocked drainage field due to solids carried over from the septic tank/sewage treatment system. If you do not maintain (arrange emptying of) your system, solids can pass through the tank and therefore block the downstream drainage field.

Generally, to rectify the situation, an engineer would need to replace the drainage field – jetwashing may occasionally be an effective solution, but this is on a case-by-case basis and advice should always be sought by a qualified engineer.

Poor performance
System is overloaded: if too many people are using the septic tank for the size, it can become overloaded.

Tank requires emptying: if the tank is not emptied as recommended, this can reduce performance.

Chemicals and other biological inhibitors: high concentrations of detergents and cleaners will cause poor performance. The O&M manual for each system gives an overview of limitations, appropriate concentrations etc.

If you have concerns about your septic tank, give us a call on 01388 537050.