The Flow Rate of a Garden Hose

Garden hose GPM

One of the most important aspects of gardening is irrigation. The watering of your plants can benefit from using an appropriate hose. Being aware of the flow rate of your hose comes in handy. This will preclude the purchase of a hose that is not suitable for your requirements.

Here are the answers to some common questions regarding garden hose flow rates.

What Is A Garden Hose Flow Rate?

Defining what a garden hose flow rate is should be a good place to start.

A garden hose flow rate is the volume of water that flows through a given length of hose at a certain pressure.  That amount is generally expressed in gallons per minute or GPM.

For example, a garden hose may have a flow rate of 10 gallons per minute (GPM). That means you can run 100 gallons of water through your hose reel in 10 minutes.

When you know this, you can also determine how many garden hose gallons per hour are being delivered. This is particularly useful for calculations of tasks needing a high volume of water such as filling a swimming pool.

There are several factors that affect garden hose flow rate. It is simply the amount of water that can travel through your garden hose in a minute. This is commonly referred to as GPM or gallons per minute.

You can also calculate the number of gallons delivered per hour if you know the GPM.

9 to 17 gallons per minute is a typical garden hose flow rate. An average garden hose would have a GPM of around 12 to 13, but the type of hose can affect this.

If you use a device that outputs water at a high velocity, such as a pressure washer or a spray nozzle, your faucet GPM can also affect its water output. You should also consider the burst pressure of your hose. If you are using a sprinkler or nozzle, try to get a hose with a burst pressure greater than 350 PSI.

What Can Affect GPM

Hose Diameter

A normal garden hose will be available in a 1/2, 5/8, or 3/4 inch size. This measurement is the internal diameter of the hose. Your current hose is likely one of these sizes.

The smaller the diameter, the lower the GPM, and fewer gallons of water can travel through it per minute. This causes a limitation on the amount of water that you can be provided to your garden within a certain amount of time.

Water Pressure

The majority of hoses that are available in stores have a garden hose PSI rating. PSI means pounds per square inch which means the speed at which water travels through the hose.

The pressure provided from a normal water tap is about 40 to 60 PSI. In some cases, this can be up to 80 PSI. In some homes, the installation of pressure regulators is required to reduce the level of PSI.

To gain an accurate calculation of your garden hose flow rate, you will need to know the PSI of the water from your faucet. You can find this out by attaching a pressure gauge.

Hose Length

As the hose gets longer, the flow rate decreases. A large reduction in flow rate can occur if the water needs to travel over a longer distance.

For example, a 3/4″ diameter 50ft hose with a 50 faucet PSI would supply 28 GPM. The same hose of 100ft in length would supply 19GPM. That’s a significant difference from using a longer hose.

Sharing The Water Supply

If water is being used elsewhere from the same supply, this can also negatively affect your hose GPM. If you are using a washing machine, a dishwasher, or a kitchen sink is running, you can expect the flow rate of your hose to be reduced.

Calculating Your Garden Hose Flow Rate

The calculation to accurately determine the flow rate of a garden hose can be quite complex. The simplest way is to use an online calculator but you could also use a large 5-gallon bucket and a stopwatch.

Here is a table of the common garden hose lengths when using an outlet pressure of 50 PSI.

25ft Hose

Hose DiameterGPM
1/2″28.0
5/8″48.0
3/4″80.0

50ft Hose

Hose DiameterGPM
1/2″14.0
5/8″24.0
3/4″40.0

100ft Hose

Hose DiameterGPM
1/2″7.0
5/8″12.0
3/4″20.0

Your Hose Efficiency Requirements

When you are calculating the flow rate for a garden hose that you may purchase, the efficiency that you require depends upon the size of your garden and how often you water it.

If your garden often has issues with standing water, you only need a lower flow rate.
It will take longer for the water to saturate the ground, so watering is required less often.

If the soil absorbs water quickly, more water is required. A hose giving a higher flow rate can reduce the amount of time that is required to spend watering.

When a hose is s combined with a sprinkler can also affect the GPM.

How To Improve Your GPM

The length of your hose and its internal diameter is both dependent on the type you purchase. But there are other ways to improve the pressure and therefore the GPM.

  • Inspect for leaking or breaks in the pipes. They can trickle water out over time. To check for a possible leak, turn off all faucets and your home’s water valve. Then, record the number that appears on your meter. Leave it for a few hours before checking the reading again. If this has increased, you may have a leak.
  • Ensure all of the valves are fully open. Many are quick to question their water pressure before checking their valves are completely open. Ensure that all faucets are in the open position; they may have been knocked during maintenance work or damaged without realizing it.
  • Check your hose for clogs and kinks. In many cases, a clogged or kinked section in a hose can reduce water pressure. Hose piping may develop interior residue on its over time that can reduce water flow, However, if you undergo maintenance on a regular basis, this should not be an issue.

At the same time, it is imperative to make sure that your hose’s not being twisted or kinked at any point. Remember that to effectively manage a good flow rate for your garden hose; you should consider the size of your garden, the types of plants that you have, and how regularly they need to be watered.