Large (3/8”) hoses are designed for all professional models and some prosumer-grade gas pressure washers. These hoses can withstand serious water pressure up to 10,000 psi. Plus, they're thicker to allow greater water volume (more gallons-per-minute).
Does hose diameter affect water pressure? A Larger diameter hose helps maintain the current water pressure as there is less resistance to the natural flow. A smaller diameter restricts the water flow, and in turn reduces the water pressure, but it increases the velocity (speed) the water travels.
When the pipe diameter is too small, resistance is created. This leads to a reduction in the water flow and an increase in pressure. On the other hand, an oversized pipe can lead to a sluggish flow. This diminishes the efficiency of the entire water system.
For flows under 5 GPM and a hose up to 100', I'd say 5/8'' will work just fine. For a 5 GPM flow, the difference between a 100' 5/8'' and a 100' 3/4'' hose is only about 5 psi. At 5 GPM a 5/8'' hose is losing 9 psi / 100ft compared to a 3/4'' hose losing 4 psi. Where it gets interesting is when we go to 7+ GPM.
The size of a pressure washer hose is important because it affects the amount of water that can flow through the hose, which in turn affects the amount of pressure the pressure washer can generate.
It all depends on if you are using it for the inlet or outlet of the pressure washer. If you are using it on the inlet side, the answer is yes you can use a 100 ft garden hose. But there are going to be some drawbacks compared to using a shorter hose.
If your hose is 100 feet or less, no, your hose will not likely have issues. However, if you want to use a hose that is a few hundred feet long, you will lose a noticeable amount of water pressure. Most pressure washers are not sold with long hoses because the best pressure is achieved from a shorter hose.
Hose diameters range from 3/8-inch, 1/2-inch to 3/4-inch. In the United States, most standard garden hoses are 5/8-inch in diameter. The bigger the diameter, the more water is delivered. The bigger the diameter determines how much hose can be put on any of our water hose storage products.
The Science of Hose Lengths
Assuming a best-case scenario – working on flat ground and normal operating conditions – you typically won't lose much pressure as you increase the length of hose that you use. For instance, on a 3/8-inch hose with a 3 gallon/minute flow, the loss of pressure per 100 feet is about 50 PSI.
A quick and easy way to increase water pressure is to adjust the pressure-reducing valve, which can be found in your home, usually close to your water meter. If your pressure gauge reading was low, make slight adjustments to your regulator.
Effect of Hose Diameter at Low Pressure: For garden watering, using a hose with a larger diameter can significantly increase the flow rate. For example: A 100ft long 3/4 inch diameter hose can deliver about 22 GPM at 60 psi. A 1/2 inch hose of the same length delivers around 8 GPM.
The screw acts as a water pressure regulator. If you tighten the screw the water pressure will be more and if you loosen the screw the water pressure will be less. Turn the screw clockwise to tighten it and increase the pressure, or turn it counterclockwise to decrease the pressure.
For example, if the diameter of a pipe is reduced over a very short distance, you'll be able to observe the resulting increase in pressure quite noticeably, as in the garden hose scenario above.
The Weeper Hose works best with low water pressure, so we advise only having the water running lightly.
Here's the thing to remember about garden hose dimensions: A larger diameter of hose carries more water per minute. A larger diameter hose can also be useful in handling differences in water pressure. For example, if you are pushing water uphill through a hose, it will be more beneficial to use a large diameter hose.
Using a tape measure, measure from that distance to the spigot or outdoor faucet you'll attach your hose to. Choose a garden hose that is slightly longer than your measurement.
For the same discharge compared to a ⅝ inches pipe, a ¾ inches pipe have comparatively higher pressure output but at a reduced velocity. A ¾ inch hose delivers significantly more water than a ⅝ inch hose. For instance, a 25-foot ¾ inch hose can output up to 72 gallons per minute, nearly double that of a ⅝ inch hose.
Low pressure at your garden hose spigot can be caused by one or a combination of issues, such as clogged or leaking pipes, excessive corrosion in the spigot valve or a lack of water pressure coming from the street.
Check the main water supply pipe and find the valve next to the meter. You can tighten or loosen the bolt at the top of the valve to increase or decrease water pressure respectively. Tighten the bolt in small increments at a time, then use the pressure gauge to see when you reach the right PSI between 40 and 60.
Large (3/8”) hoses are designed for all professional models and some prosumer-grade gas pressure washers.
This may not seem like a big difference, but it impacts on the amount of water and pressure that can flow through the hose. A 3/8 inch hose can handle more water flow and pressure than a 1/4 inch hose, which means it can clean larger areas and tougher stains more effectively.
These are maximum recommended flow rates, and this chart is based on a maximum acceptable pressure drop of 15% per 100 feet of hose.