The length of time it takes a well to replenish is not only influenced by the ground water source and well pump. The water well casing, water table, type of ground, weather conditions, and well depth play significant roles.
So how long does it take for a water well to refill? A 6-inch well diameter with a depth of 300 feet can store around 450 gallons of water. Most domestic water wells have an average well water refill rate of 6-10 gallons per minute which means it will take anywhere from 45 minutes to two hours to refill.
Sourcing reliable information on something as important as a water well is not as easy as it should be. This article delves into the refill rate of water wells from trusted authorities.
How Much Time Does A Water Well Take To Refill?
Determining the time for a well to refill varies according to the location. So, to get a more controlled reading, one should test the flow rate during a dry period.
To calculate the water well’s length of time to refill completely, you must first work out the yield. The well yield is the amount of water supply a well can deliver in a given period.
The yield also determines the maximum amount of water that can be used from the well. This maximum amount ensures that the borehole water level remains above the well pump.
Your average residential water well has a 6-inch casing—these 6-inch boreholes store around 1.5 gallons of water per foot of standing water.
A decent depth for these types of water wells is 300 feet. So, one of these wells with a flow rate of 10 gallons per minute would indeed take about 45 minutes.
But, boreholes widely come with well casings in two sizes: a 6-inch and 10-inch casing. Plus, the wells range from an average of 80 to 300 feet deep.
So, it helps to know how to calculate your flow rate.
How To Calculate Water Well Refill Rate?
To calculate the water flow rate, you need the well casing diameter, the water storage footage, and well depth.
You first need to calculate the number of gallons your water well can store.
Working Out Water Well Storage
The 6-inch and 10-inch casing water wells store different amounts of water.
You can calculate the amount of water the well can store by multiplying the water storage capacity (per foot) by depth of the well.
6-inch Casing Water Well Storage
This group of water wells stores 1.5 gallons for every foot down.
An 80-feet well can then store 120 gallons (80 feet x 1.5 gallons).
Similarly, the category of 300-feet wells stores 450 gallons (300 feet x 1.5 gallons).
10-inch Casing Water Well Storage
These 10-inch types of wells store about 4 gallons for every foot.
An 80-feet well will store 320 gallons (80 feet x 4 gallons).
Likewise, 300-feet wells can store 1 200 gallons (300 feet x 4 gallons).
Well Refill Rate
The wells refill rate is dependent on the type of well pump and how porous the earth is to allow the flow of groundwater back in.
Types of Well Water Pumps include:
- Submersible pump
- Jet Pump
- Centrifugal Pump
- Shallow Well Pump
- Hand Pump
Flow rates should be tested and be above five gallons per minute (5 GPM). This rate means that the well will pump out 300 gallons in an hour (5 GPM x 60 Minutes).
This amount of water produced in an hour is essential because of peak demand. Peak demand is when a home draws the most water in an hour, usually in the morning and evening.
Water wells need to produce water that meets the peak demand or exceeds it. Otherwise, there will be a period when the well runs dry.
A flow rate for a small family can be about 6 GPM, but a more reasonable flow rate would be 10 GPM.
Calculating Water Well Refill Time
The last step is quite simple once you know your well’s storage capacity and flow rate.
To work out the time it will take the water well to replenish is the total well water storage divided by the water flow rate. The returned answer will be in minutes; so divide by 60 to get the time in hours.
6-inch Casing Water Well Refill Time
In practice, an 80-feet well with a 5 GPM flow rate will take around 24 minutes to fill up.
This refill time is calculated by taking the 80-feet well storage capacity of 120 gallons and dividing it by the 5 GPM flow rate.
Similarly, we get a refill time of 45 minutes for a 300-feet well with a 10 GPM flow rate.
10-inch Casing Water Well Refill Time
A similarly average well depth of 300 feet (1200 gallon storage / 10 GPM) will take about 120 minutes (120 minutes/ 60 = 2 hours), given a flow rate of 10 GPM.
Determining Water Well Peak Hour Demand
Knowing how long the well takes to refill is liberating and helps you plan how you will use the water.
It is equally helpful to know the amount of water you need at your busiest hour of water usage, especially if you plan to install a water well in the future.
A single person uses between 50 and 100 gallons every day. This amount does not even come close to denting the water produced by the well.
However, the issue is the simultaneous demand for water well supply. Multiple morning showers, teeth brushing, and shaving can quickly use any stored water in the well. Quick water usage guides show amenities and general usage estimates, and a typical peak hour morning can draw 80 to 300 gallons.
What Can Cause A longer Refill Time?
Well Casing Deterioration
A well casing is a tube placed within the hole of the well after it has been drilled. It acts as a barrier to prevent soil and debris from getting into the water.
Over time, the well casing that is in contact with groundwater can start to deteriorate. This will cause the well to have a lower flow rate and take longer to refill.
Broken Well Screen
A well screen sits at the bottom of the well and allows water to pass through but acts as a filter to keep out rocks, soil, and dirt.
Over time, the well screen can also get clogged with dirt and debris, reducing the flow rate and increasing the refill time.
Broken Well Cap
A well cap sits at the top of the well and prevents debris, rainwater, pollutants, insects, and small animals from falling into the well.
If the well cap on top of your well is damaged or broken, it can introduce debris from the surface that clogs or damages the pump.
A broken or damaged well cap can also reduce the groundwater pressure that flows into your well. This will increase the refill time as less water enters.
Damaged Well Pump
Ultimately, if your well pump is broken or damaged, it will not be able to pump water into your home effectively. This can cause the refill time to increase significantly.
One way to reduce the refill time is to invest in a high-quality well pump with a long lifespan that operates efficiently.
Incorrect Well Placement
If your well is not properly placed, it can cause groundwater to flow off in the wrong direction. This will reduce the amount of water available for your well and increase the refill time.
Another potential well placement issue is when the well is not drilled directly into an aquifer. An aquifer is a body of porous sediment or rock that gets saturated with groundwater.
If the well is drilled directly into the aquifer, it gains access to large amounts of water storage. If the well misses the aquifer, it means less access to that water and longer refills times for your well.
Aquifer permeability can also play a part in longer refill times. Permeability determines how easily water can pass through sediment and rock in the aquifer. Higher permeability can result in faster refill times, and low permeability could slow down refill times.
Periods of Drought
Aquifers are primarily recharged by rainwater seeping into the ground. If the area you live in gets impacted by long periods of drought, it could affect the aquifer recharge rate.
The aquifer recharge rate is when the aquifer replenishes its water storage. Lowers levels of water in the aquifer will naturally mean a slower refill time for your well.
Age of the well
As a well gets older, the casing, screen, and cap will all degrade. This can cause a number of the issues we have already discussed that will lead to longer refill times for your well.
It is essential to have your well regularly inspected and maintained by a professional to ensure that it is in good working order and prevent any potential problems that could lead to longer refill times.
Working out the time it takes for a water well to refill is simple but extremely helpful. The time varies greatly depending on the well casing diameter.
Wells should have a minimum flow rate of 6 GPM, and you should avoid anything under 5 GPM because it would increase the refill time. Most domestic water wells will produce more than enough water in a day, but the peak hour demand could affect the overall supply in a given period.
Frequently Asked Question (FAQs)
Will a Well refill Itself?
Yes, a well will refill itself. This occurs as groundwater seeps into the aquifer and is absorbed by the surrounding soil and rocks. The rate of recharge depends on local rainfall levels, aquifer permeability, and the age of the well.
Additionally, damage to the well casing or pump can impact how quickly water flows back into the well, affecting refill time.
It is essential to invest in regular maintenance and repairs to lower recharge times and ensure your well remains in good working order.
How fast should a well refill?
The speed with which a well refills will depend on several factors. Factors including the well casing diameter, the depth of the aquifer, and the permeability of the surrounding soil and rocks. In general, deeper wells will take longer to refill than shallow ones.
On average, a water well should refill anywhere within 45 mins to two hours.
Additionally, damage to the casing or pump can impede water flow and result in a slower refill time. A minimum flow rate of 6 gallons per minute (GPM) is recommended for most domestic wells. Anything below 5 GPM can begin to impact refill time.
What happens if you run your well dry?
Running a well dry means depleting the water supply in the aquifer that the well is drilled into. This can have several negative consequences, including reduced groundwater levels, slower refill times for your well, and potentially damage to your well pump or casing.
In order to avoid running your well dry and minimizing its impact on recharge time, it is essential to monitor your water usage and invest in regular well maintenance.
Additionally, during periods of extended drought, it may be necessary to restrict water usage in order to conserve the groundwater supply.
How can I increase my well’s flow rate?
There are a few ways you can increase your well’s flow rate. One way is to invest in regular well inspections and maintenance, which can help keep your well pump and casing in good working order.
Additionally, you can explore options for water conservation, such as switching to low-flow plumbing fixtures or installing a rainwater collection system.
Alternatively, suppose your well’s flow rate is consistently below 5 GPM. In that case, you may want to consider drilling a deeper well or installing an alternate water source such as a rainwater collection tank.
Ultimately, the best way to increase your well’s flow rate will depend on the specific factors impacting its recharge time.
What do you do when your well runs out of water?
When your well runs out of water, there are several steps you can take to address the situation. The first step is to determine what has caused the aquifer’s depletion and whether it is due to damage or normal wear and tear on your well system.
This can involve consulting a professional, such as a well inspector or pump technician. Once you have determined the cause, you can take steps to repair or replace any damaged equipment.
Additionally, you may need to restrict water usage to allow the aquifer time to recharge. It may also be necessary to drill a deeper well or install an alternate water source in some cases.
How long do Wells last?
A water well can last anywhere from 25 to 100 years; however, there is no definitive answer to this question, as the lifespan of a well depends on several factors.
Factors include the diameter and depth of the casing, the materials used in the well, the geological makeup of the surrounding soil and rocks, and how well the well has been maintained.
Some wells may last for decades without needing any repairs or upgrades, while others may need to be replaced after only a few years. Ultimately, the best way to ensure your well lasts for as long as possible is to invest in regular maintenance and repairs.
Additionally, if you live in a high water table area, you may need to replace your well more frequently than those who live in drier regions.