Should a neighbour's drain or septic tank be overflowing, it is likely to cause you great concern. The fact that you are worried about the problem is more than likely mirrored by your neighbour.
You are then strongly advised to tell whoever is responsible that their drainage is faulty, causing a leak of waste water. You should do this in a friendly manner, and explain exactly what problems you are suffering, such as odours, or your inability to use your garden..
You may be able to arrange for Severn Trent Water to arrange for the clearing of a shared drain (a public sewer), in which case the service is free. Contact Severn Trent on 0800 783 4444.
If, however, the fault relates to a septic tank, or a drain, it is up to the householder to contact a drainage contractor in order to remedy the situation. Drainage contractors are plentiful, and can be found in the Yellow Pages, or via a search online.
If you feel that you are unable to talk to your neighbour, you may wish to write to them instead using a standard letter template. You should make two copies of your letter, give one to your neighbour, and keep the other for your records.
If after a reasonable period, two weeks for instance, no improvement has been made, you can then consider going to court and making a complaint to the Magistrates' bench. The court makes a charge for this service, and you may get costs awarded against you. If you do wish to make such a complaint, you should contact the Magistrates' Court in Castle Street, Worcester (01905 743200). Write to the Court to make an appointment, stating that you wish to start action under Section 82 of the Environmental Protection Act 1990. The Court will advise you of where and when to attend.
If the above actions prove to be unsuccessful, then please ring Worcestershire Regulatory Services (01905 822 799) for advice and, where appropriate, further investigation.
This DOCUMENT explains in detail how you can take this action.