Drinking and potable water are obtained from spring, rivers, lakes, artificial or natural alluvial areas, wells and, if mandatory, water from purifying the sea water even though expensive. However, rainfall is the most important source of all these water resources.
We can classify the drinking and potable water into three main groups according to formation and supply format:
-Rainwater (the water collected in cisterns)
-Surface waters (rivers, lakes, dams, etc.)
-Groundwater (spring and wells)

Groundwater: They are the waters obtained from springs and wells. They are fed by rainfall and surface waters. Obviously, these water resources are interrelated although we discuss in separate titles.
Well water: It is formed by the accumulation of water filtration into the ground. Groundwater is brought to surface through opening of the wells. Just as in the springs, both primary pollution control and secondary pollution control and pollution precautions for well waters should be paid attention.

Groundwater should be tested before use and implement after that although they are usually clean and can be put into use directly. Because, presence of natural contaminants such as nitrite, radiation etc. in the soil (primary pollution) is a possibility. The main problem in the utilization of groundwater is the prevention of pollution in a place where it is obtained/received (secondary pollution). For these reasons, at the point where groundwater emerges, some precautions should be taken whether groundwater emerges naturally (spring water) or artificially (well). Otherwise it can become harmful to health through polluting here again.

Disinfection of wells
At least annually, well water must be poured and the walls must be thoroughly cleaned with a brush.
It must be 30 to 100 meters away from midden and similar structures, depending on the permeability of the soil. Such structures should be inferior to the well and located facing downwards according to propensity to place.
Well wall must be terminated 60 -70 cm higher from the ground surface (well curb) and the mouth should be closed with a suitable cap. The remaining land surface around the well curb should be covered with a waterproof material, 2 to 3 meters in diameter, (well platform) and the surface water coming from the edge of the curb and surface crack should be avoided.
Animals should be prevented from entering the well and the surrounding area through enclosing with a fence/wire around 10-15 meters of well.
The mouth of the well should be closed continuously, taking water from the well with the pump should be preferred, if it is not, cleaning of winch, rope and bucket of the well must be respected. Well water should be examined in each season and the quality should be checked whether it has been corrupted or not.

Groundwater Quality Standards

Pollutants Quality Standards
Nitrates 50 mg/L
Active substances in pesticides containing relevant metabolites degradation and reaction products 0.1 µ/L
0.5 µ/L (total)(1)

(1) “Total” related metabolites are the sum of each plant protection product determined and calculated in monitoring procedure containing degradation and reaction products.
Manual of Threshold Values for Symptoms of Groundwater Contaminants and Pollution
SYGM and DSI define the mass of groundwater under risk to reach the targeted good chemical status of groundwater; SYGM identifies and publishes the threshold values for all pollutants and symptoms of pollution and groundwater quality standards. The following list of minimum parameters which should be taken into account in determining the threshold values will be considered.

Parameters
Arsenic
Cadmium
Lead
Mercury
Ammonium
Chloride
Sulphate
Trichloroethylene
Tetrachlorethylene
Conductivity

Additional parameters and threshold values ​​for these parameters can be determined using the list in Annex 9 according to the specific situation of groundwater and/or basin mass as a result of investigations carried out by SYGM.

Organohalogen compounds and substances capable of forming such compounds in surrounding water
Organophosphorus compounds.
Organotin compounds.
Substances and preparations or derivatives with carcinogenic or disruptive manner (mutagenic) features or proved to have properties that may affect the steroidogenic, thyroid, reproduction or other endocrine-associated activities around or through water.
Persistent hydrocarbons and persistent and bio-accumulable organic toxic substances.
Cyanides
Metals and metal compounds
Arsenic and arsenic compounds
Biocides and plant protection products
Suspended solids
Substances which contribute to eutrophication (in particular, nitrates and phosphates)

Groundwater Monitoring
For general-purpose monitoring of groundwater masses, main following parameters are monitored:
– Oxygen content,
– PH value,
– Conductivity,
– Nitrate,
– Ammonium.
Selection of groundwater monitoring points should be made in a comprehensive and easily understandable manner for the chemical status of groundwater. Frequency of monitoring should be done to provide representative tracing data of results of analysis.