Guidelines for Minimum Standards in Water Well Construction, Province of British Columbia — June 1982
Part 2 — Technical Information Appendices
APPENDIX 7: WATER SAMPLES AND ANALYSES
1. Introduction
Water in all wells should be sampled and the necessary field and laboratory tests made so that the ground water chemical and bacteriological quality of each well and its suitability for its intended use can be determined.
Recommended Water Quality Standards have been published by the Provincial Ministry of Health Services for drinking water and the reader is referred to this publication for further details. The Ministry of Health Services should be contacted for advice on what additional analyses may be required and on any constituents present in well water which are above the recommended safe limits.
The Environmental Laboratory, Ministry of Environment provides a water quality check program. This program is a service whereby individuals may obtain analyses of their private water supplies in order to generally determine its suitability for domestic purposes. This service is provided at a subsidized cost, to individuals using or planning to use a water supply. It is not provided to commercial enterprises, consultants, organizations, societies or corporations; nor for the purposes of legal evidence.
The following analyses will be performed on samples submitted under this program:
Total Alkalinity
Calcium
Total Hardness
Total Iron
Magnesium
Fluoride
Nitrate
Nitrite
pH
Dissolved Solids
Specific Conductance
Turbidity
Total Coliforms
It is emphasized that:
- This program does not replace in whole or in part any other program existing within the government services.
- The interpretation of the report, with respect to water treatment and health problems, will not be made by the laboratory. The Environmental Laboratory will refer such queries to the health districts.
The above analyses are the only ones available under this program.
2. Chemical Quality and Collection Procedures
Water quality field testing kits are useful for early determinations after an aquifer zone has been penetrated. Results based on field kit tests should only be used as a guide and are no substitute for a full laboratory chemical analyses.
Sample collection procedures vary from the use of a bailer - common to the cable tool method to more sophisticated samplers which can take a water sample at a specific depth. Usually samples are collected from the discharge during test pumping or after the production pump is installed. Laboratories have certain procedures that must be adhered to on the collection and submission of samples for chemical analyses including requirements for certain field tests.
A list of recommended parameters for chemical analyses is given below.
3. List of Recommended Parameters for Chemical Analyses*
| |
Units |
| Phen. Alkalinity |
mg/L |
| Total Alkalinity |
mg/L |
| Sulphate (SO4=) |
mg/L |
| Nitrite and Nitrate (NO2 + NO3) |
mg/L |
| Total Kjeldahl Nitrogen (TKN) |
mg/L |
| Total Phosphorous (P) |
mg/L |
| Fluoride (F-) |
mg/L |
| Chloride (Cl++) |
mg/L |
| Calcium (Ca++) |
mg/L |
| Magnesium (Mg++) |
mg/L |
| Sodium (Na+) |
mg/L |
| Potassium (K+) |
mg/L |
| Manganese (Total and Dissolved) (Mn) |
mg/L |
| Iron (Total and Dissolved) (Fe) |
mg/L |
| Silica (SiO2) |
mg/L |
| Sp. Conductance |
umhos/cm at 25°C |
| pH |
relative units |
| Total Dissolved Solids (TDS) |
mg/L |
Total Hardness (CaCo3) |
mg/L |
| Turbidity |
(JTU) |
| * Additional parameters may be required where known or suspected sources of pollution exist. |
4. Bacteriological Quality and Collection Procedures
A sample should be taken on all wells to determine bacteriological quality. For new or repaired wells AWWA AIOO-66 recommends the collection of any sample for determination of bacteriological quality be taken following the disinfection of the well. Chlorine solution must first be removed from the well by pumping, and the chlorine residual reduced to less than 2 ppm before the sample is taken. Special care must be taken in collecting the sample to avoid contacting the inside of the bottle or the cap with the fingers.
The local public health inspector should be requested to obtain a sample for bacteriological analyses when the water is to be used for a public water supply system. In situations where this is not possible, sample bottles and advice on sampling techniques may be obtained through the local health district.
5. Reliability of Sample Results
The quality of any drinking water supply cannot be determined with confidence from the result of a single sample but rather is possible only by observing the results of several samples over a long period of time. Shallow wells that may be influenced by surface contamination near the well may produce water of varying quality, depending on the climatic and physical conditions. Therefore, if a sanitary survey shows a well water supply to be obviously subject to pollution, the water may be condemned irrespective of the test results.
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