More and more mortgage and insurance companies, chartered surveyors, and prospective house purchasers recognise the value of a pre-purchase drain survey.

Drains might be out of sight, but they should never be out of mind – particularly if you are buying a new home.  It is fair to say that few people do much to maintain their drains (indeed, evidence of regular ‘maintenance’ is often a clue that there is a problem!)

At the very least, a survey will identify areas of the drainage system that require some minor maintenance work to prevent relatively minor problems, such as blockages or foul smell. At worst (or best, if it prevents you buying a house with a serious problem) the survey might discover a serious drainage problem that would cost thousands of pounds to put right- and this is not uncommon.

There are generic potential drainage problems in houses and drains of all types and ages; for example:

Victorian Terraced Houses:
The rear extensions of Victorian terraced houses often suffer from subsidence due to leaking drains. If the original salt-glazed clayware drains, they are now over 100 years old and possibly suffering the effects of time, such as cracked pipes and porous pipe joints.

1960’s houses and bungalows: there is every chance that the drains are constructed with pitch fibre pipes. This type of pipe is now banned and for good reason: they have failed the test of time. Pitch fibre drains have a tendency to delaminate, deform and blister; conditions that tend to gradually worsen until blockages become a problem. As the pipes lose their circular shape they lose their strength; pipe collapse being the inevitable conclusion.

Modern Houses:
The days of professional drain-layers have sadly passed (except at , of course!). All too often nowadays, the drain-laying at a housing development is left to un-skilled labourers and the digger driver, with the job priced in such a way that the drains have to be laid in a hurry, with almost inevitable consequences that might take some years to surface.

Any Estate Housing built since October 1937: Many housing estates built since 1937, including many current developments, have common sewers that are not adopted as “Public Sewers”. Often, these sewers run through front or back gardens rather then under the road. Such shared sewers are deemed to be “Private” and thus the shared responsibility of all those properties that use them. This can lead to very difficult situations when maintenance or repairs are required. Although all the properties should contribute to the cost, many owners are either unaware of their obligations or just refuse to pay their share. Often, just one or two properties on a line of perhaps ten or twelve houses actually suffer the consequence of a problem, such as flooding, and it can be very difficult to convince unaffected house-owners that they should contribute to repair costs. Sometimes, the only recourse is to legal action and/or the involvement of the local authority’s environmental health officer.

The Rural Idyll:
Such properties are very likely to have ‘private drainage’, i.e. a septic tank (sometimes mistakenly called a cess pit), which is totally reliant on a sub-soil soakaway that is capable of absorbing all the waste water from the house, which can often be in the region of 40 gallons per day per person (and rising, as we make more use of washing machines and dishwashers). Soakaways rarely last for ever and replacements can cost thousands of pounds. Worse still – the septic tank might just discharge to a stream or ditch, causing environmental damage that again can cost thousands of pounds to deal with.  

Any House Connected to a Public Sewer: If the public sewer is in the road, the drain that leads out to the sewer is usually “private” and thus the responsibility of the house-owner, even where it is under the road. Any damage to the drain under the road will inevitable be very expensive to repair – usually in the thousands of pounds.

Leaking Drains:

One of most serious drainage problems, that affects ALL types of property, is the threat posed by leaking drains. Leaks can occur for many different reasons, the most common being when drains become cracked or broken as a result of general deterioration or tree roots infiltrating the drain. Over time the water that leaks from the pipe will wash away soil from around the pipe and surrounding area, resulting in a void or area of soft ground around the pipe. If this drain is near or under a property, as they commonly are, then this will frequently result in subsidence, leaking drains being recognised as the cause of up to 40% of property subsidence cases.

There are many tell-tale signs of subsidence, including; cracks evident in brickwork and window sills; sunken steps or paving; and cracking of drive-ways or paths. However, although these problems are evident in numerous properties around the country, few people are aware that it’s leaking drains that are causing the problem. Ironically, with such cases it is of paramount importance that the problem is identified and the offending drain repaired as quickly as possible, as repairing a leaking drain is usually far cheaper than repairing subsidence!

A Homebuyer’s Survey will help identify all the problems outlined above (and other potential drainage problems too numerous to mention here) and all for little more than the cost of having a simple blockage clearance!

For more detailed information regarding the content of the survey, or the report that compliments it, we recommend that you click here or refer to the ‘cctv survey’ section within ‘our services’.