Private Water Supplies - Case Study

Lack of risk assessment on an historic regulation 9 supply


This case study concerns a private water supply which serves a community in Devon. The water is derived from a spring source in a rural catchment, predominantly used for farming. It provides a supply of water for domestic purposes, mainly to private residents, although some properties are rented by their owners for short term tenancies.

Figure 1. Spring source collection chamber

The number of people using the supply has grown since the supply was first established over one hundred years ago, when it was developed primarily to serve a manor house inhabited by a single family and a few domestic hands. The water was however, further distributed to a few local cottages and outbuildings in the estate grounds, as well as some field troughs for watering livestock. At that time, the supply system was controlled by the local landowner and maintained by day to day local custom and practice within this small and contained community. Over the subsequent decades, the number of buildings and inhabitants – both permanent and transient, changed the use with a greater proportion being for drinking water and other domestic water use, rather than livestock and irrigation. This has meant a greater reliance on the water supply and its infrastructure bringing associated risks to sufficiency and quality.

For regulatory purposes, the supply is classified as either a large supply or one that is used as part of a commercial or public activity. The manor house is now a listed building and divided into several separate apartments and managed by board of shareholders, i.e. property owners.

The water is in part, still derived from the original catchment source but can now be supplemented by water from an additional private borehole located nearby on the manor house estate. This water is then stored in a small brick-built reservoir (figure 3) which gravity feeds into a central treatment system and is then distributed internally throughout the building to the various apartments for domestic purposes. The structure and integrity of this reservoir is original. It remains unchanged and unimproved. For example, the cast iron vents, as shown in figure 2, are still in place. Figure 3 shows the roof of the reservoir from the inside.

Figure 2. The air vent on top of the reservoir showing the age of the system.
Figure 3. A view of the inside of the shared reservoir.

The farmhouses, which were once part of the manor house estate, were gradually sold and are now in private ownership, with many of the estate outbuildings now converted for domestic use properties. These are either owner occupied or rented. Some of the property owners have installed their own boreholes, which form supplies to single dwellings. Nevertheless, they have still retained a connection to the historic system and are therefore they are still an integral part of this supply.

The distribution system serving these buildings has, over time, been extended and passes across and through the various buildings and various parcels of land that they occupy. As a result, knowledge of the supply has become fragmented and the details of the arrangements are incomplete. Consequently, opportunities to isolate individual parts of the system are now limited.

Over the years, ownership of management of the water supply has changed and been variable in its commitment. At one time a Manor House committee took care of the day to day running of the system on behalf of all consumers, including routine maintenance of the raw water reservoir. Costs were apportioned accordingly. In total, there are approximately 70 consumers on this supply.

More recently the maintenance of the raw water collection system has become more ad-hoc with those residents in the converted farm buildings required to take action to maintain sufficiency of supply and maintenance of the raw water collection system. An attempt was made to bring everyone together to manage all the shared water supply system, but this failed to establish a management strategy or agreement.

The evolution of the supplies described above, has brought about disagreements about how the water supply should be managed and today there remains no cohesive or legally binding arrangement in place. Management of it is fragmented and unreliable. Unfortunately, civil matters of this nature are not uncommon and often become exacerbated with time as assets deteriorate and improvements costs rise and become more frequent, and as property ownership change hands.

The changes in the regulations in 2009, which empowered the local authority to enforce where appropriate, can enflame these disputes further where accountability is not always clear, yet improvements are mandatory. Whilst a landowner and consumers are all relevant persons as defined in section 80 of the Water Industry Act 1991, this does not necessarily confer any responsibilities on how costs and responsibilities are apportioned. These are matters that can only be settled between the relevant persons by way of their agreement (preferably legally binding). This process may be further complicated by historic clauses and easements that are written into individual document deeds.

Local Authority Activity

Following the conversion of the manor to apartments, and prior to the implementation of the Private Water Supplies Regulations 2009 the local authority began to undertake routine sampling of the water from the manor house to establish its quality on an annual basis. This sampling however did not include any other points of consumption at the privately owned properties (formerly farmhouse and outbuildings), which were also on the same supply. Although the legislation has never specified that this must be the case, the Inspectorate considers it best practise for sampling points to be alternated from time to time or rotated to give a wider representation of the water consumed across a supply of this nature. Over the duration of approximately 30 years, this monitoring gave rise to several coliform detections and breaches of the lead standard.

In 2010 The Private Water Supply Regulations 2009 were implemented, which included a requirement to risk assess supplies (except those to single dwellings only) and to review this risk assessment every five years. This gave the local authority the opportunity to understand private water supplies in their areas in their entirety, by site surveys to determine any hazards that posed a potential danger to human health, or the wholesomeness of the water consumed. The first assessment of this supply carried out by the local authority was in 2014 but it is understood not to have been shared with the manor management committee. As a result, no action was taken in response to its findings.

By 2019, the risk assessment was due for review, thus giving a further opportunity for the local authority to revisit the infrastructure and use any enforcement powers as necessary to bring about improvements. The status of this is not known.

Up until this point it is likely that many of properties on the supply were being occupied on a temporary basis, without too great a demand on the supply system. However, the consequence of the pandemic and need for the population to stay at home, and in some case isolate or shield, it is possible to have resulted in a greater occupancy of the buildings and apartments using the supply all the time. Inevitably this would have placed an unprecedented demand on water usage and potentially caused changes in water quality and any subsequent public health risk . For those supplies on spring sources such additional usage has resulted in sufficiency challenges and this is particularly apparent in private water supplies. Fortunately, with day-to-day vigilance of a dedicated few, and some self-imposed restrictions of non-essential use by most consumers on the supply, the system remained trouble free throughout 2020. However, the age of the infrastructure (especially parts underground), the extension and complexity of the supply, an increasing demand, reducing water resource and the diminishing understanding of the supply configuration, it is possible sufficiency may become a problem in the future. One thing is certain, the current arrangement cannot be maintained indefinitely. Whilst civil disagreements over ownership and costs between relevant persons exist, the situation is likely to deteriorate further without urgent action. The need for a comprehensible risk assessment is an essential part of long-term planning to secure a safe and sufficient supply.


Ageing supplies, of which some can be over 100 years old, were not originally constructed to cope with the demands of growing populations or the intensity of consumption by modern appliances used for a variety of domestic purposes. Equally, without improvement they will only become more problematic with time and use.

It is essential that a risk assessment is carried out to identify changing risk with changing times and uses. This case study shows an example of a private water supply that is in urgent need of a risk assessment so that a comprehensive plan of action can be prepared. It is unacceptable and a risk to health, that 10 years have lapsed since a risk assessment was first required and, as yet no outcome is available to residents. Without a risk assessment there remains no long-term plan for any contingency arrangements should the supply become insufficient during periods of drought.

It is often the case that private water supplies are vulnerable to loss of supply and upon which, in this case, 70 consumers could be without water. The outcome for the consumers and the local area would be significant.