Drip Irrigation Fails Without Flushing

Q. I changed my drippers to adjustable types and have problems with them working in my backyard. I fix them either by adjusting or removing the heads. Now they work fine. This happens throughout the year but I have never seen so many fail at the same time. My front yard also uses adjustables but don’t have the same problems. I was thinking about going back to drippers for reliability. 

Variable flow or adjustable drip emitter above and below.Do you like to play Whack a Mole? If you do, then you will love adjustable chip emitters.

Close-up of an adjustable or variable drip emitter. I don't hate them but I don't like them very much and give precision drip irrigation a bad name.

These are precision drip emitters that met or release water at specific volumes over a given time, usually one hour. They are color-coded by the manufacturer to indicate how many liters or gallons per hour they release. The pointed end is pushed through a hole created by a punch specifically meant for drip tubing. Do not use a nail or Phillips screw driver to make these holes. Spend four dollars and buy a punch.I call these types of emitters "precision drip emitters" to differentiate them from variable drip emitters which are extremely imprecise in their delivery of water.

This is a flag-type precision drip emitter called so because of the triangular flag. The flag has a stem attached and can be removed from emitter for easy cleaning. I like them because they are so simple to use, inexpensive and easy to clean if they get plugged.

A. I call “dippers”, “drip emitters” or “emitters” but I think we are talking about the same thing. I work with drip irrigation all over the world. The major reason drip systems fail is because the system is not cleaned and “flushed” regularly. Flushing and cleaning drip systems must be part of a regular maintenance schedule.

            When cleaning and flushing a drip system, the primary filter or screen must be cleaned

Screen filter called a "Y-filter" because it's at an angle like the letter "Y".This black housing can be twisted open and inside there will be a screen filter which should be washed and flushed to remove sediment and debris. There is a round On the top which can be opened for flushing the inside of the screen but it does not remove everything.

thoroughly, every “dead end” must be opened and flushed with several gallons of water and emitters should be inspected for plugging when they are operating. If emitters are plugged, they must be cleaned or replaced if they cannot be cleaned.

The ends of polyethylene tubing or drip tubing can be bent over and this double ring device can be slipped over the end. This double ring keeps the tubing bent over to stop water flow but also allows the end of the tubing to be opened quickly and flushed to remove debris and sediment.Some people have used electrical tape to do the same thing but these are inexpensive and fast.

This is auto flush for drip irrigation. The double ring above must be open manually. This can be inserted inside the drip tubing and flushes the polyethylene pipe every time the valve comes on. I would still recommend flushing the lines manually periodically and after repairs but this helps reduce some of the labor.

            A major problem is created when drip systems are repaired and but not flushed afterwards to remove dirt that enters the drip lines. If drip irrigation lines are cut and repaired, I guarantee dirt entered these drip lines. It is mandatory that the “dead ends” associated with the repair are flushed immediately afterwards.

            Drip system filters are cleaned and the system flushed because dirt or sediment in the water collects inside the filters and eventually plug drip emitters. Flushing the irrigation lines removes algae and bacteria that plug emitters as well.

            How frequently to clean and flush a drip system depends on the quality of the water and how much water flows through the system. Irrigation systems should be flushed more often in summer than winter.

            How long it takes to flush and clean depends on the design of the system. Poorly designed drip systems take longer to flush and clean. When designing drip irrigation systems, minimize the number of “dead ends” so that flushing the system takes less time and there are fewer places that accumulate “dirt” and slime.

            Most drip irrigation systems attached to municipal water are flushed once a month if the municipal water delivered is clean. Sometimes it is, sometimes it isn’t, depending on the age of the municipal system.

            Even though filters must be installed as part of every drip system, small amounts of sediment pass through these filters and eventually become a problem if the system is not flushed and cleaned regularly. Failure of drip systems is gradual, not like an “on and off” switch.

            Drip systems attached to well water should be flushed more often because this water is “dirtier”. How often depends on the quality of the well water which varies from well to well. Typical cleaning and flushing might vary from weekly to biweekly during the summer months.

            Algae and bacteria (you might call it “slime”) grow inside every irrigation system. Algae and bacteria are not problems with most sprinkler systems but can be problems with drip emitters because the “emitter” holes are so small.

            In my opinion, drip irrigation systems must be flushed and filters cleaned on a regular basis depending on the quality of the water and the gallons used. The drip emitters used should be easy to clean and inexpensive. Variable drip emitters are inaccurate in their delivery of water but are subject to the same plugging as all other drip emitters.