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How Deep Should a Well Be for Drinking Water?

Scott Winfield
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by Scott Winfield

How deep should a well be for drinking water? Wells should be at least 100ft deep, but this depth can reach 500ft or even 1000ft in some cases. The ideal depth depends on multiple factors such as the local geography and how deep the water table is.

How Deep Should a Well Be for Drinking Water
A Deep Well

How Deep Is the Average Well?

As the Water Systems Council notes, most wells are between 100ft and 800ft deep, although most people stop drilling around 500ft This range is far too broad for an average nationwide.

Instead, it’s better to consider the local depth for wells. The United States Geological Survey maintains an outstanding database with this information.

Many areas of the country have water tables more than 100ft below the surface, which is why 100ft is the shortest depth for wells in most regions.

The depth of the water table isn’t everything, though. As a general rule, deeper is better when digging a well because depth gives water more time to filter through rocks and get rid of contaminants, ensuring the water is safer to drink.

However, water from deep wells may also have more hard water minerals, so people tend to install water softeners.

In other words, an area may only need a well 150ft deep, but people might dig down to 200, 300ft, or even more because they want a better well.

Why Shallow Wells Are a Bad Idea

The real question here is what’s the safest depth a well should be?

Shallow wells (defined as 50ft or less) are a bad idea because they may get water that picks up contaminants as it passes through surface aquifers.

Possible sources of contamination include things like barnyards, sewers, septic systems, or chemicals from manufacturing facilities.

Water that goes deeper through the ground passes through multiple layers of rock and soil, where various biological, chemical, and physical processes remove contaminants. The result is that a sufficiently deep well has naturally purified water, while a shallow well is far more likely to make you sick.

Factors to Consider Before Digging a Well

Here are some factors to consider before you start digging a well.

Accessibility

Wells are typically more helpful if they’re in an accessible area. If you only have to walk out into your yard to access it, that’s a very different situation from having to walk a quarter of a mile every time you want to use it.

The ideal location for a well is usually as close as possible unless the other factors on this list force you to install it further away.

Budget

According to HomeAdvisor, most wells cost between $15 and $30 for each foot down they go. A cheap well may cost around $1500 for digging, while a deep well may cost $12,000. Most people will pay more than $5000 just for the drilling, which doesn’t include permits or systems like pumps or water heaters.

Local Geography

Most areas are suitable for digging wells. However, too much rock in the area can stop water from flowing through it, which negatively impacts the ability of wells to function.

In most areas, local governments have information on whether or not wells are suitable in particular areas.

Industrial Locations

Wells should always stay far away from industrial facilities, including manufacturing plants, dumps, and anything else that regularly uses chemicals. Trying to place a well upstream from such facilities isn’t always a good idea, either.

Water may flow one way on the surface, but it could flow in another direction underground.

Proximity To Other Wells

Wells should be as far as possible from any other well in the area. Placing wells too close together can reduce the amount of water available to each, possibly below the point where using a well is viable.

If you expect many people to need water in one area, it may be worth digging a single large, extra-deep well.

Surface Water

Surface water sources can be bad for wells. Any regular source of surface water, such as a river, may contain contaminants from agricultural, biological, or industrial sources.

These are bad to put into your drinking water, so it’s best to keep wells a good distance away from them. Ideally, a well will be at least 100ft away from surface water.

Waste

Like surface water, the presence of biological waste can contaminate local water. These areas have a realistic possibility of containing various pathogens.

Special Considerations

Every well is installed in a unique spot, so the considerations for digging them can change.

For example, an area may have exceptionally high water flow throughout the region, allowing wells to exist nearby without threatening each other’s water supplies. If this is the case, you don’t need to worry about proximity.

On the other hand, an otherwise-ideal site may be a local cultural or spiritual site. Even if it’s the ideal spot, a well is usually good enough if you dig it elsewhere, so you don’t necessarily have to get the best site.

How to Dig a Well To the Required Depth

The best way to dig a well to the required depth is to hire a professional well-digging company to do it for you. However, if you want to dig a deeper well yourself, you may need to get a pneumatic drill.

These are available online and require buying a potent air compressor to run them. Depending on local conditions, a pneumatic drill can usually dig a well in days to weeks.

How to Dig a Well To the Required Depth
How to Dig a Well To the Required Depth

Regardless of how you plan to get your well, you should check with your local government offices to learn more about the type of soil you have. The best office to talk to varies by area, but it’s usually part of an agriculture department. They can provide logs from other drillers in the area.

Remember, even experienced drillers can’t perfectly predict what to expect. However, knowing what’s common in an area will still give you a realistic range of things.

Finally, make sure you check up on any other local regulations or guidelines and get the appropriate permits before you start.

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Scott Winfield
Scott Winfield
My name is Scott Winfield and researching and writing about water filters and other strategies to purify water has become my full time passion in recent years. I'm glad that you found our site and you can look forward to authoritative and well researched content here to help you get the best in water.
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