Do You Know Your Flow?

Irrigation

When you come into Wes-Tech, it is important that you ‘know your flow.’ This will determine the type and amount of watering equipment that can be used in your system. In order to help our staff give you guidance on designing a successful working system and putting together the parts you need, we need to know:

–    How much water you have (your flow)
–    The pressure (psi)
–    What you are planning on watering (including potential future add-ons)

Once we know your flow and what you’d like to water, we can help you find the best sprinkler for your needs and show you the range that each product works best in. To test your flow, Wes-Tech has a Toro Pressure and Flow Gauge for both purchase and rent. At a minimum, you may also perform what is known as a ‘bucket test’. A link may be found here: https://www.youtube.com/watch?v=MGIScmrw76k

Why Should We Know This? Flow is important to know because there are many different sprinkler types, whose output is measured in gallons per minute or gallons per hour. Once you know your flow, make sure to leave yourself a 20% buffer. The buffer accounts for friction losses when water moves through the equipment. For example, if you have 5 gallons per minute (gpm) of flow, realistically you can safely use 4 gpm. If you need all 5 gallons, nothing will be able to perform. It is common to split your watering areas into two or more sections, to accommodate more watering – the new zones would work in succession to maintain adequate pressure.

The average home hose tap operates at about 50psi – beware, there are exceptions, plus or minus. A hose tap at 50 psi will have roughly 4 or 5 gallons per minute available. The ideal flow is “as much as you can get,” but available water flow determines the type of sprinkler you can use as well as the zone count.

For example: 5 gallons at 50psi will run a large amount of drip line (1gph/foot) in gardens, flower or vegetable beds. Another choice might be several micro sprays or bubblers for garden beds or shrubs. For lawns, inground sprays or rotors are the norm. With rotors as an example, you’d be lucky to get 4 rotors spraying 20ft at the same time – they would use about 1 to 1.5 gpm each. Running lawn rotors on 5gpm may not be realistic. Rotors also require 30-40 psi running pressure for best performance.

It is also important to consider elevation changes around the yard (hills, balconies) and long distances. Elevation and distance mean extra friction loss which can affect flow and pressure. You might need to up-size your delivery pipe to have enough flow available.