Artesian Well: What It Is, and What to Do About a Flowing Well

What makes a well artesian

The USGS says groundwater between layers of poorly permeable rock, such as clay or shale, may be confined under pressure. When a well taps that confined aquifer, water rises above the top of the aquifer. It may even flow onto the land surface. The water is under artesian pressure, and the aquifer is an artesian aquifer. Source: Artesian Water and Artesian Wells.

The level the water rises to in a tightly cased well is the potentiometric surface. If that level is below the ground, the well does not flow. If it is higher than the wellhead, the water comes out with no pump. That is a flowing artesian well. The word comes from Artois in France, where well known flowing wells were drilled in the Middle Ages.

A deep well is not always artesian. The USGS says people often call deep wells artesian, but great depth alone does not make a well artesian. The term means water confined under pressure below layers of relatively impermeable rock. It also says artesian water is really not different from other groundwater. It only reaches the surface a different way.

Artesian well or flowing well

Michigan EGLE says that in artesian wells, water rises within the well to a point above the top of the aquifer. If it also rises above the ground surface, the well is a flowing well, or flowing artesian well. All flowing wells are artesian, but not all artesian wells are flowing wells. Source: Fact Sheet: Flowing Wells (PDF).

• Geology or ground shape. EGLE says artesian conditions come from the geology or from the shape of the land. So flowing wells are often found in lower areas near rivers or lakes.
• Weather. EGLE's handbook says barometric pressure can move the water level of artesian aquifers. Owners sometimes report changes in flow or cloudy water during stormy weather. Source: Michigan's Flowing Well Handbook (PDF).
• The well record. Michigan's Water Well Manual says that for a flowing well, the static water level is above the ground surface. Source: State of Michigan Water Well Manual (PDF).

Flowing wells in Michigan

EGLE's Flowing Well Handbook says flowing wells are found throughout Michigan, from aquifers in glacial drift or in bedrock. Its figures:

• About 200 flowing well districts were identified in the Lower Peninsula in the early 1900s.
• In 2018 about 110 flowing wells were drilled in Michigan, about 0.7 percent of new water wells. Their average flow before flow control was 13 gallons per minute.
• Gladwin, Roscommon and Cheboygan counties have the most flowing wells drilled each year.
• Flowing wells are abundant in towns such as West Branch, Rose City, Cedar, Indian River, Onekama, Conway, Oden, Alanson, Naubinway and Rapid River.

To see the wells near you, use the Michigan well record lookup. The handbook says the Wellogic database and EGLE's scanned well records are extremely useful for finding flowing well areas.

What Michigan's well code says

• The flow stays in the casing. EGLE says the state well code requires the flow to be confined within the well casing.
• A deviation can allow flow. A well owner can ask the local health department for a deviation. The owner or the driller must show that control of the flow is not practical, that control will likely bring sand or turbidity, or that the water has a beneficial use, such as a pond for irrigation or fish, or heating and cooling.
• New wells only. EGLE says the flow control rules apply to new well construction, not existing wells.
• Hire a contractor. In known flowing well areas, the handbook advises property owners not to drill their own wells and to hire a registered water well drilling contractor.
• Other permits. If a new flowing well drains into a wetland, lake or stream, the handbook says more permits may be needed. Ask your local soil erosion or zoning officer.

What to do about a flowing or uncontrolled well

Water coming up outside the casing. This is a breakout. EGLE says an ineffective seal around the casing can let water discharge on the outside of the casing pipe. That can wear away the ground, flood the well site and nearby land, and damage nearby buildings. The handbook says the owner should know he or she is legally responsible for correcting it, and a water well drilling contractor should be consulted immediately. Turbid water from around the casing needs immediate attention.

An old well that has always flowed. Leave the flow alone until a contractor looks at it. EGLE says trying to stop or reduce the flow from older flowing wells can be risky. Many have defective seals or corroded casings. Restricting the flow at the wellhead can send the water upward along the casing. EGLE says letting the flow continue until the well is plugged may be the safest option.

One case in the handbook (Ogemaw County, 1989): an owner spent about $15,000 trying to stop a flow himself and did not succeed.

A flowing well you no longer use. EGLE says plugging an abandoned flowing well requires special practices. The state code requires neat cement or concrete grout. If water leaks around the casing, that space is sealed first. The handbook advises against putting a building over a plugged flowing well.

For questions, call your local health department or EGLE's Environmental Assistance Center at 800-662-9278.

Outside Michigan

Rules for flowing wells differ by state. This page quotes Michigan's rules only. In another state, ask your state well program or your county health department before anyone works on a flowing well. Our guide to finding a well pro explains what to ask.

Test a flowing well like any other private well. See how to test well water and the certified labs by state. To find your well's depth and water level, see how deep is my well.