Source: Manual of Individual Water Supply Systems,
PA-430/9-74-007, U.S. Environmental Protection Agency
In rural areas springs often are used for water supplies. Springs occur where groundwater discharges to the land surface. Depending on the geology of an area, the discharge may bubble from a fairly distinct point, (e.g., from fractured bedrock) or may surface as seepage areas with no well-defined discharge point, as when an impervious layer of soil channels groundwater to the surface.
Although springs can be a good source of water, they may not provide enough water throughout the year to be a reliable supply. Many springs are fed by water that is fairly close to the soil surface so that during periods of drought there may not be enough water in these areas to keep the spring flowing at a sufficient rate.
Another problem with springs fed by shallow groundwater is that they are contaminated easily by microorganisms and other pollutants from the land surface. For this reason it is important that no contamination sources be located upsiope from the spring and that any surface runoff be diverted away from the spring development. Fencing to keep livestock out of the catchment area is advisable. Because springs are so easily contaminated, installation of disinfection equipment usually is necessary.
Springs that become muddy shortly after a rain shower probably should not be developed as water supplies because surface water provides much of their flow. These springs are likely to be highly unreliable and may be contaminated.
Before proceeding with development, the total daily flow from the spring should be estimated to ensure that it at least equals the daily water need. (Provisions for peak water use can be met by using a storage tank.) To make a crude estimate of the spring's flow, the flow rate should be measured during the lowest flow period (usually in the late summer or fall) by constructing a temporary clay dam below the spring to channel the water. A pipe is placed through the dam and the time required to fill a container of known volume is recorded. Then the flow rate is calculated.