Residential surveys: drains

What the eye can't see

7 November 2016

In the first in a series of articles, Martin Beattie and Graham Ellis explain why out of sight should not mean out of mind

When it comes to drains, one limitation of a standard home survey is that assessment is based on a visual inspection, in accordance with guidance in the RICS Home Survey services professional statements or RICS UK professional guidance Surveys of residential property, 3rd edition. The extent of the survey should therefore be made clear to a potential client at the outset before agreeing terms of engagement.

Drain inspection: RICS Home Survey services

Each mandatory professional statement includes a description of service, setting out for the client what the surveyor will do, and contains the following guidance for surveyors in section G6.

Survey level one: RICS Condition Report

Services are generally hidden in the construction of a property, which means that only the visible parts can be inspected and the surveyor does not conduct specialist tests. The visual inspection cannot assess the efficiency or safety of:

  • electrical, gas or other energy sources
  • plumbing, heating and drainage installations, or whether they meet current regulations
  • the inside condition of any chimney, boiler or other flue; inspection covers to the underground drainage systems are not lifted, neither are the systems tested.

Survey level two: RICS HomeBuyer Report

As with the RICS Condition Report, the surveyor can only inspect the visible parts of the available services for a HomeBuyer Report and does not carry out specialist tests or assess their safety or compliance with regulations. Drainage chambers are, except in the case of flats, inspected visually from ground level – where it is safe and reasonable for the surveyor to lift covers – but neither the drains nor drainage systems are tested.

Survey level three: RICS Building Survey

As with the Condition and HomeBuyer Reports, the surveyor only inspects the visible parts of the services. They do not carry out any specialist tests other than through their normal everyday operation. Intermittent faults of services may not be apparent on the day of inspection.

As stated in the mandatory professional statement for surveyors (G6 Drainage):

'The surveyor opens all reasonably accessible, lightweight inspection chamber covers within the curtilage of the property. The assumed routes of the drain runs and their general condition are reported, based on a visual inspection. Where a water supply is available and turned on, the surveyor may also run water through the system as part of the inspection; they must attempt to identify the means of foul and surface water disposal. There have been changes to legislation with which the surveyor should be familiar before undertaking the inspection.'

Drain inspection: Surveys of residential property, 3rd edition


If there is no visible sign of anything untoward, how can the surveyor be certain that everything is as it should be below ground level?

The guidance in the RICS Home Survey professional statements is mirrored in this document for members who undertake their own format of surveys.

Survey level one (e.g. Condition Report)

The surveyor will not lift inspection chamber covers.

Survey level two (e.g. HomeBuyer Report)

The surveyor will lift accessible inspection chamber covers (where it is safe to do so) and visually inspect the chamber(s).

Survey level three (e.g. Building Survey)

The surveyor will lift accessible inspection chamber covers where it is safe to do so, and observe the normal operation of the services in everyday use. Their ability to do so will be restricted where properties are empty, drained down and services disconnected. Assuming all services are connected and functioning fully and safely, normal operation usually includes:

  • turning on water taps, filling and emptying sinks, baths, bidets and basins, and flushing toilets to observe the performance of visible pipework, when the surveyor considers these appropriate in assessing the system
  • lifting accessible inspection chamber covers to, for example, drains and septic tanks, where it is safe to do so, identifying the nature of the connections, and observing water flow where a water supply is available.

In all cases, the surveyor will advise the client that further tests and inspections are needed if the owner or occupier does not offer evidence of appropriate installation or maintenance, or the client seeks assurance of their condition, capability and safety.

A surveyor will often inspect the drains while looking at the grounds. Again, this is a visual inspection only. RICS Home Surveys requirements for the three survey levels are the same.

Inspecting grounds: RICS Home Surveys services

Each mandatory professional statement includes a description of service, setting out to client what the surveyor will do.

Survey levels one and two: RICS Condition Report and RICS HomeBuyer Report

The surveyor inspects the condition of boundary walls, fences, permanent outbuildings and areas in common (shared) use. This means walking round the grounds and any neighbouring public property where access can be obtained.

Survey level three: RICS Building Survey

The surveyor inspects the outside of the property as in survey levels one or two. However, where there are restrictions to access, these are reported and advice given on any potential underlying risks that may require further investigation.

As stated in the 3 mandatory professional statements in section H (Grounds): 'Surveyors should perform a visual inspection only of the grounds by walking around, where necessary, from adjoining public property'. This requirement also includes shared areas for flats.

Inspecting grounds: Surveys of residential property, 3rd edition

Survey level one HomeBuyer Report

The surveyor will carry out a visual inspection of the grounds during a general walk around, and where necessary, from adjoining public property; the inspection should also include the inside and outside of all permanent outbuildings not attached to the main dwelling, where access is possible.

Survey level two

The inspection will be similar to that described above, under level one.

Survey level three

There is a higher level of expectation for an inspection at this level. In addition to that described for level one, surveyors should perform a thorough visual inspection of the grounds, and, where necessary, from adjoining public property. Specific defective features and other matters associated with the grounds can be costly to resolve and may affect the client’s purchasing decision. Consequently, the surveyor should fully account for these during a level-three service and follow the trail of suspected problems to a greater extent than at levels one and two. Examples include assessing retaining walls in danger of collapsing, deeply sunken paths or driveways, dilapidated boundary walls or fences, and considering the legal and insurance implications.

Where the site inspection detects evidence of a problem or a perceived risk such as a structural problem to the building or other constructions, a misconnection, evidence of back-up or overspill, detection of vermin infestation or risk of root damage, the surveyor may have good reason to recommend further investigations in the report to the client or stakeholder. This will be within the client’s expectations provided it has been explained at the outset.

A word of caution

Even accepting the limitations of an inspection, if there is no visible sign of anything untoward, how can the surveyor be certain that everything is as it should be below ground level? There is a strong case for every survey to include an inspection of the underground drains.

Graham Ellis MRICS is Associate Director of RICS Residential Professional Group and Martin Beattie is Vice-Chairman of the National Association of Drainage Contractors

Further information

Download a complete “Residential surveys: drains” PDF