What is the Average Temperature of Well Water? (*It Depends)

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Noticed anything unusual about your well water temperature? Wondering what the average groundwater temperature should be, and which factors affect this temperature?

You’ll find all the answers to your questions in this guide.

📌 Key Takeaways:

  • The average temperature of well water is 35 to 77 Fahrenheit (1 to 25 Celcius).
  • Shallow wells of less than 30 ft deep are more susceptible to changes in atmospheric temperature, and are usually 2-3 degrees above the average annual water temperature.
  • Deep wells of more than 30 ft below ground are colder. For every additional 64 ft below the initial 30 ft, the water temperature drops by about 1 degree.

🌡️ What’s The Average Well Water Temperature?

Well water is usually sourced from an underground water source, so your well water temperature will be the underground water temperature in your area.

Well water, being underground, usually has a more stable, consistent year-round temperature than surface water, like river or lake water.

The average groundwater temperature for wells is 35 to 77 Fahrenheit (1 to 25 Celsius). There are a few factors that affect the likely temperature of the water in a well, which we’ve discussed later in this article.

Generally, the deeper the well aquifer, the colder the water.

Deep wells (below 30 ft) are colder than shallow wells (10-30 ft). That’s because they’re drilled through an impervious layer of rock and earth to reach an underlying supply of water. The temperature of the water in a deep well drops by about 1 degree for every 64 ft below the initial 30 ft below ground.

Shallow wells are more likely to be affected by weather changes since they’re only drilled down far enough into the ground to become below the water table, and are closer to the land surface.

Measuring well water temperature

⏳ Can Well Water Temperature Change Over Time?

Does the temperature of the ground water in your well stay the same, or might it change gradually over time?

Well water can certainly change in temperature over time. Even wells deep below the earth’s surface are affected by the mean air temperature aboveground.

Usually, the temperature of the ground water in a well will rise and fall by a couple of degrees throughout the year to reflect the changes to the local climate.

📊 Factors Affecting Average Well Water Temperature

Below, we’ve listed the most common factors that affect the temperature of well water in the US.

Air Temperature

Regardless of the well depth, the temperature of the ground water will be affected in some way by the local climate.

As an obvious example, you can expect well water in Florida to be a few degrees warmer than the well water in Minnesota due to the air temperature differences throughout the year.

Well Depth

The depth of a well also affects its temperature.

The general rule is the deeper the well, the colder the water. Groundwater temperatures are colder in deep wells because there are more layers of soil and rock between the aquifer and the air above.

In comparison, a shallow well has less insulation above the aquifer, meaning that it’s more likely to become warmer when the climate gets warmer aboveground.

Contractors drilling a shallow well

Surrounding Geology

Local geology plays a role in the groundwater temperature, and subsequently, the temperature of well water.

Some types of rocks and soils are more porous and less dense than others. This difference in thermal properties affects the temperature of the water flowing through them.

Wells in regions with sandy, porous soils are likely to have warmer water than wells in areas with dense, heavy, clay-based soils.

Time Of Year

Finally, the water temperature in a well is affected by the time of the year.

In regions that experience periods of warm and cold weather, the well water temperature will fluctuate with the climate. The extent of the temperature changes to the well water based on seasonal changes depends on the well depth.

In the summer, the increased surface temperature of the ground may result in well water that’s warmer by a couple of degrees. In the winter, the opposite happens: the surface temperature is lower, and so is the groundwater temperature.

👨‍🔧 Related: Solving the Winter Woes: Dealing with a Frozen Well Pump

🤔 Can Well Water Be Too Hot Or Too Cold?

You should never get hot or frozen well water, so technically, well water can never be too hot or too cold.

However, there are a few effects of very cold well water. Your water heater will take longer to warm up the water, which might mean you need to upgrade to a high-performance heater, and your water bill will be higher.

Plus, you might have very hard water if your groundwater well supply is very cold because minerals like calcium and magnesium dissolve more easily in cold water.

Getting water from a deep well

❔ Average Temperature Of Well Water: FAQ

What is the normal temperature of underground water?

The normal temperature of underground water is 35 to 77 Fahrenheit. However, this temperature depends on how deep underground the water is stored, the temperature of the ground itself, the density of the rocks and soils surrounding the water, and the local climate. Generally, the deeper the well and the denser the surrounding earth, the colder the water.

Is well water cold or warm?

Well water should be cold. The water won’t be warm unless you’ve managed to tap into a geothermal spring (unlikely). Your well water might be warmer than its average year-round temperature during summer months when your local climate is hot, causing the sun to heat up the pipes carrying water from the well into your home.

Can well water freeze?

Yes, well water can freeze in the pipes connecting the well to the home in colder climates. However, this shouldn’t be an issue for pipes installed beneath the region’s frost lines (usually around 3 to 5 feet beneath the surface of the ground, depending on the local climate). The well itself shouldn’t freeze because wells are tens of feet deep beneath the ground, and the earth holds onto heat, preventing the water temperature from dropping below freezing.

What is the temperature of well water in Michigan?

The average temperature of well water in Michigan is 45°F. Groundwater temperatures vary depending on the well depth and the time of the year. Deeper wells maintain a more constant temperature in Michigan than shallow wells.

What is the temperature of deep well?

The temperature of a deep well is about 35 to 50 F. The exact temperature of the well is influenced by its depth (expect the water temperature to drop by 1 degree for every 64 feet below the initial 30 ft depth), the surrounding geology, and the climate of the well location.

Can you adjust the temperature of well water?

No, you can’t adjust the temperature of the water in a well. However, you can, of course, use a water heater to adjust the temperature of your water once it’s in your home. The vast majority of water heaters let you adjust the water output temperature to suit your needs. You can use a thermometer to measure the temperature of your hot water and adjust the water heater’s setting bit-by-bit if you need to achieve a specific temperature.

  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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