PLEASE READ ALL OF THESE NOTES BEFORE TAKING A WATER SAMPLE
SUPPLIES NOT IN USE AT THE TIME OF SAMPLING
If a supply has been out of use for any length of time, or a property has been unoccupied, the water which has stood in pipes may have undergone substantial changes in composition. In these circumstances it will be necessary to run water to waste until the system and content properly reflect normal conditions of use. Flushing the system may perhaps take an hour or so, but some systems may have to be pumped and flushed for a day or several days, depending upon the nature of the source and the volume of the water contained in the distribution system. In the case of well supplies, care must be taken not to pump the well dry since this will tend to disturb any sediments present and might damage a submerged pump in addition to drawing water from previously untapped contours. If a well has been out of use of a long time, further advice should be sought before sampling.
WHERE TO TAKE THE SPECIMEN
Under normal circumstances a sample of drinking water should be taken from the kitchen tap since this is the outlet from which drinking water will generally be drawn. This will then indicate the cleanliness or otherwise of the whole system. However, sometimes it is appropriate to take the specimen from a suitable point as close to the source as possible, so that the specimen reflects the quality of the water available at source with minimal risk of needless contamination from the various parts of the distribution system. Obviously where contamination from within the system is suspected, it will be necessary to seek further advice, as it may be necessary to take several specimens in order to identify the source of contamination. If a specimen is taken from a tap, proper precautions may be taken. The inside surface of the bib of a tap is usually covered with a slimy accumulation of bacteria which will contaminate the specimen. Before taking a specimen from a tap it is necessary to sterilise the tap in the manner described below. Mixer tap are difficult to sterilise and should not be used for sampling a supply unless this is unavoidable. Plastic taps or taps with plastic inserts cannot be sterilized with a flame.
STERILISING A TAP PRIOR TO SAMPLING
If a blowtorch is not available, or if the tap has a plastic insert, then the tap may be sterilised by slowly pouring a kettle full of boiling water over the outlet of the tap and then repeating this a second time
TAKING THE SPECIMEN
The bacteriological tests employed are extremely sensitive and contamination of the specimen is likely unless these instructions are followed. Great care must be taken to prevent anything from coming into contact with the inside of the cap and the neck of the bottle. The following procedure should be adopted:
1. If a bacteriological examination is required sterilise the tap by flaming and then allow the water to run to waste for several minutes before taking the specimen. This will flush out any water which has been standing in the pipes.
2. While the water is running please complete the enclosed submission form giving details of the source as far as possible and record details on the label of the bottle. It is advisable to use a pencil or ball-point pen on the label as this may become wetted during sampling. Water washable inks should not be used.
3. Fill the bottle to within about half an inch of the neck and replace the cap.
4. Return the bottle and submission form for the analysis to the laboratory to arrive within one day of sampling. If you are in doubt about where and how to take a specimen please telephone the laboratory, when a member of staff will be pleased to discuss the matter with you and advise accordingly. It is especially important to seek advice about sampling any supply which has been out of use for a long time. Please let us know if you are delivering sample to us or sending it by courier so that we can try to make sure that there will be someone available to receive it!
DIRECTIONS TO OAKWATER LABORATORIES FROM M5
At the roundabout by the Weary Traveller pub, continue straight on, first exit, signposted Town Centre.
At the roundabout by Tesco’s, continue straight on, second exit, signposted Town Centre.
At the traffic lights, turn left onto the High Street, signposted Broadclyst.
Continue through the town and at the next roundabout take the second exit, signposted Bradninch.
Continue up over the hill and down the other side into Bradninch.
As you come into Bradninch, take the first turning on the left, Parsonage Street No. 1 is the first house on the right.
If there are no parking spaces in Parsonage Street, further parking is available on Hornbeam Gardens, which is the first turning on the right.