New home construction in New Hampshire often means drilling a new well. Many water well drilling companies base their price on the depth of the new well, so new homeowners want to know how deep the well has to be dug to give them reliable, clean water. They know the deeper the well, the higher the cost.
Do your water well research
In most cases, you can find out how deep your neighbors’ water wells are by contacting state agencies. In New Hampshire, the state began keeping records of all new wells in 1984, including their depth. The information is available to the public in an online database. By examining how deep the wells are in your surrounding area, it gives you a general idea of how deep your water well will need to be.
Bedrock Water Wells
Most new wells dug in New England today are bedrock wells. These wells are constructed by drilling deep into the bedrock below the soil and tapping into the water that flows between the rocks. This water is general high-quality, although it may come with some minor issues, such as hard water.
One advantage of a bedrock well is they are less affected by drought than shallow wells. In general, drought effects can be lessened even further by drilling a deeper well.
The average depth of a bedrock well for household use is about 300 feet deep but most are 100 to 500 feet. A few can be more than 1,000 feet deep if the geology and underground water source require it.
What’s the yield?
Depth of the well is most dependent on yield, or how much water flows from the well in a given period of time, usually measured in gallons per minute (gpm). The average well in New Hampshire yields about 6.5 gpm. If a 200-foot well yields only a few gpm, the NH Department of Environmental Services recommends the well be dug deeper. However, if the well is 700 feet deep, having a yield of 4 gpm may be sufficient because the deeper depths mean the well is less likely to be affected by drought.
A more comprehensive way to measure yield is to look at the flow over a longer period of time. TheWater Well Board recommends for domestic indoor use a minimum volume of 600 gallons of water flowing into the home within a two-hour period at least once per day.
Geology plays a role in your water supply
Most of New England is lucky to be located above a rich supply of clean water. However, there are some areas of the region in which the geology of soil and bedrock plays a role in how deep the well must be dug. Your well drilling company should consult with the United States Geological Survey to examine rock formations, water table depth, likely changes to the water table or changes to water quality. You can also contact the USGS and review documents online.
Skillings & Sons has nearly 40 years of experience in the well drilling business and can answer your questions about drilling a new well for your home. Contact us about water well drilling and hydrofracturing.