Water

Swimming pool water quality

In order to maintain acceptable quality the following parameters should be maintained:

  • pH 7.2 - 7.6

  • Free Chlorine 1.0 - 2.0 mg/l

  • Combined Chlorine residual should be kept as low as 0.5 mg/l and should be no more than one-third of total chlorine.

  • Total Alkalinity 80 - 150 mg/l

  • Calcium Hardness 200 mg/l minimum

  • Total Dissolved Solids (TDS) maximum 1000 mg/l above supply water TDS to an absolute maximum of 3000 mg/l (2000 mg/l preferable)

  • Sulphate 360 mg/l maximum

Water balance is affected by:

  • Temperature

  • pH

  • Total Alkalinity

  • Calcium Hardness

  • Total Dissolved Solids

The Langelier formula, sometimes called the Saturation Index, is used to determine pool water balance. The Saturation Index (SI) = pH + Temperature Factor (TF) + Calcium Hardness Factor (CF) + Total Alkalinity Factor (AF) minus Total Dissolved Solids Factor (TDSF).

The value obtained should fall between 0 and 0.5 and indicates the water is in balance.

Private water supplies

The Regulations with regard to Private Water Supplies changed at the beginning of January 2010 when the Private Water Supplies Regulations 2009 came into force. The Regulations categorise Private Water Supplies depending on the volume and use of the supply. A 'Large' supply is one that supplies on average daily volume of more than 10m3, or 50 persons or more, or where the water is used for a commercial activity or to public premises. A 'Small' supply includes any private supply that provides less than 10m3 per day to two or more dwellings or less than 50 persons. Any supply that provides water to a single domestic property is defined as a 'single dwelling' supply.

The Council is also required to carry out Risk Assessments of Large and Small supplies to determine any likely problems with the wholesomeness of the supply. Risk Assessments for single dwelling supplies can be undertaken if requested by the owner/occupier.

The Regulations permit Local Authorities to recover the costs in fulfilment of their duties. These duties include carrying out Risk Assessments, investigations, and taking and analysing samples. The Regulations specify these services and the maximum fees that can be charged. In addition to the specified maximum, the charges can only reflect the reasonable cost of providing the service.

The table shows a breakdown of the charges relating to the various services the Council can offer towards Private Water Supplies Guildford Borough Council's Private Water Supply Services

Activity

Maximum permitted charge

Example charging scheme

Comments

Risk assessment

£500

Hourly rate x time

Will depend on size and complexity of supply.

Sampling

£100

Hourly rate x time

Not envisaged to take any longer than an hour.

Investigation

£100

Hourly rate x time + any analysis costs

Carried out in the event of test failure, can be incorporated into a Risk Assessment.

Authorisation

£100

Hourly rate x time

Application by the owner of a supply for permission to breach a standard temporarily whilst remedial work is carried out.

Analysis of domestic supply

£25

£25

Less than the cost of a full check monitoring suite to determine basic parameters.

Check monitoring (Commercial supplies)

£100

£27.50

To determine compliance with basic parameters as specified in Regs.

Audit monitoring(Commercial supplies)

£500

£50-£100

May be higher if additional parameters are required to be sampled.