Parts of Drip Irrigation System

Q. When installing drip irrigation, what irrigation parts do I need?

Drip irrigation must have a filter and a means to regulate the pressure, a pressure regulator. https://www.digcorp.com/wp-content/uploads/digcorp/DripZone-1.pdf accessed on August 1, 2023.

A. Make sure there is some sort of filtration, a pressure regulator to lower water pressure, and a way to “flush” the irrigation lines of debris, algae, and bacteria. Many people forget the flush part because they are used to using city water which is very clean. Every drip irrigation system needs these parts. It makes no difference if the filter or pressure regulator is first but drip systems need lower pressure. It works either way (pressure regulator first then filter or vice versa) but the arrows of water flow are important.

A flush valve can be as simple as a ball valve connected to the irrigation circuit but it must be buried so it can be found and used. 
https://www.landfx.com/docs/item/202-land-f-x-drip-irrigation-design-and-graphic-conventions.html accessed on August 1, 2023.

            The flush valve (oftentimes just a ball valve or on and off valve) is placed farthest away from where water first enters the “system” and hidden from site but easily found and used. The “flushing operation” involves cleaning the filters as well as cleaning the lines of algae and bacteria with the flush valve.

            Cant say how often to flush the lines but drip irrigation MUST have clean water to operate. Well water is a "dirtier" water than city water. Wells pick up sand and other sediment that needs regular and periodic flushing. Once you get into a "rhythm" for how often to flush (every other time you water or every fifth time you water??) it doesn't change much. Just plan on it when you use well water.

Hunter screen filter and pressure regulator in a bag.

            Lower the water pressure with a pressure regulator. Water pressure from a municipality fluctuates depending on how close you are to the municipalities water pump or reservoir. A plastic pressure regulator helps lower the water pressure into the “normal range” to operate drip irrigation. The pressure of water from wells may vary. For most homeowners, the water pressure range for smaller drip systems is approximately 25 to 30 psi. For larger drip irrigation operations (half acre and above), water pressure of drip systems may need to be more than this.

All PE tubing specifies its operating pressure and other important information such as emitter distance, size of the emitters, etc.

            Water used in drip irrigation needs to be particle free. Clean it before it comes in the drip lines. Drip irrigation relies on small holes that can plug, to deliver water. Clean water requires filtration. Even though water from municipalities has been filtered, filtration is still needed for drip irrigation. Most commonly and inexpensively, screen filters (screens are 120 -130 “mesh”, which means 120 to 130 holes per each square inch) are used. The filter is added, usually after an irrigation valve.

Pressure regulators must be used to protect the drip tubing from operating at too high of a pressure. If incoming pressure is to great or fluctuates, a more substantial pressure regulator (such as brass or more permanent type) should be used. Incoming water pressure should not exceed the PE or fitting operating pressure. Rainbird pressure regulators https://www.evergreen-irrigation.co.uk/product/rain-bird-water-pressure-regulator/

            Regular flushing cleans the lines of debris, algae and bacteria. It is important to flush the lines every time repairs are made as well as regularly. Part of the “flushing operation” requires a separate “flush valve”. This is particularly true if using a fertilizer injector.

            When designing drip irrigation, I prefer the “closed loop” type of irrigation system design. That's where there is a header and footer that "close the loop". Closed loops minimize the number of places where you have to flush and “evens-out” the water pressure of the system. It costs a bit more to install but the benefits are worth it in my opinion.