While the notion that a smaller water pipe increases the pressure is widely believed and practiced, this is not completely true. This misconception is widely accepted due to the phenomena occurring when you place your thumb over the garden hose, and the water pressure seems to increase.
Does the “thumb over a hose” increase water pressure?
You must have noticed that every time you push your thumb into the garden hose, you can feel the water pressure increase against your finger. While this rationale seems appropriate to apply to increase water pressure from a hose, it cannot be based on this principle.
The water pressure in the pipe is utilized to overcome the friction generated by the walls of the garden hose. Therefore, most of the water pressure is exhausted by the time it reaches the exit. While this explanation is oversimplified, it is enough to oppose the idea that a smaller pipe creates more water pressure.
Placing your thumb over the exit merely reduces the friction encountered by the water from the walls of the pipe. Due to this, the water pressure is not completely exhausted when it reaches the exit, and therefore, the pressure against your thumb feels greater.
This process does not create any new pressure and thereby defeats the purpose of considering a smaller garden hose. To explain the phenomenon better, let’s dig into some scientific theories.
Bernoulli’s Principle states that if the speed of a fluid increases, the static pressure decreases simultaneously. Due to this, using a smaller pipe is counterproductive as the water pressure will decrease due to the increased friction. This means that the water will require a higher velocity to get through a smaller pipe, essentially decreasing the water pressure.
This phenomenon is termed the Venturi Effect, which states that fluid pressure reduces if it is flowing through a constri
cted section. This effect disproves that a smaller pipe would increase water pressure. Therefore, using a bigger pipe is recommended if you are looking for better water pressure.
There are, however, other ways in which you can increase the water pressure in your hose.
This method is designed to increase water pressure from the source. A good quality water pump will boost the water pressure and allow you to achieve the right amount of force. While this method is a one-stop solution, temporary options can be considered as well.
If you have equipped your hose with a high-powered nozzle, increasing the water pressure is a breeze. This nozzle is long with a thin tube, thereby concentrating the water going through the hose and increasing the pressure.
The diameter of the hose
Choosing a hose with a diameter that is suitable for your garden is essential. As we already know that a smaller diameter will not increase pressure, consult a professional, and assess the dimensions for your garden hose. Between 5 and 8 inches is most commonly seen as the diameter for garden hoses, which provide adequate water pressure.
Now that you are aware of the factors that affect the water pressure of your hose, you can choose the right hose to suit your needs. Purchasing smaller hoses under the pretext that they will increase water pressure is false.
James Fields is the founder of Gardener to Farmer. His passion for gardening goes back to his childhood days when he would visit his grandfather during the holidays and help him with the plants in the backyard. This has now translated to creating a dependable resource for gardening.