Down to Earth: How Drip Irrigation Systems Work

Introduction to Drip Irrigation Systems
There is a new development in the exterior irrigation systems that we see. Drip irrigation systems are proliferating. Also known as micro-irrigation systems, homeowners discovered that these systems, when properly installed, save water by targeting the water where it is needed.

They work in landscaped areas and complement the pop-up and rotating heads that we know. They run as a zone in the overall watering schedule. They run on demand. They deliver fertilizer. Larger systems used soil analysis for targeted feeding. I will focus on the smaller residential systems used for landscaping. Other applications include foundation soil moisture control, which is not covered here today.

How do they work?
Drip irrigation is the slow application of water directly to the plants' root zone. With drip irrigation, water is not wasted on non-growth areas and the system can maintain an optimum moisture level in the soil at all times with less water lost to sun and wind. The result of using drip irrigation with watering intervals is deeper roots with more abundant foliage. Weed control is an unpleasant by-product even with mulch and weed control chemicals.

System Components
These are simple systems. 1/2" & 1/4" plastic pipe, elbows, couplings, tie down stakes. Flow emitters, flow bubblers, foggers, streamjets. Pressure reducers, timers, controllers, back-flow preventers. Pipe spikes, hole punch, box-cutter, tape measure. T-connectors, Y-connectors, straight connectors, L-connectors. 9 outlet distribution manifolds, swivel adapters, hose end timers, adapter tees. Trust me, it may sound like a lot of parts, but this is not rocket science and I am no rocket scientist. So if I can learn it, anyone can.

Here in southeast Michigan in 2007, I installed a Toro Blue Stripe® drip irrigation system to water my landscaped areas because I tired of the 90+ minute watering sessions. It is a simple system with three zones. I run all three zones at once for about 45 minutes and it adequately waters my landscaped areas. This system is custom to my house, which is the beauty of the design. System water usage is high and must be monitored.

Installation
I began with a starter kit consisting of 1/2" & 1/4" pipe, connectors, emitters, pressure reducer, and installation tools. I wanted to irrigate a new tree that I planted in the front yard. The pipe runs through my lawn so I needed to get it underground. I used a lawn edger to dig the trench, I laid the pipe in the trench and covered it. Voila! I was feeling pretty good until the kit-supplied end-clamp burst on me. What to do? I fastened a 3/4 " C-clamp to the end of the pipe. Voila again. This time it held.

Customization
Wow! I can adapt this system to do all my landscaped areas. I designed three separate zones: front yard, right side yard, and rear yard. I bought the materials and installed them. I eliminated end clamps. All of the pipes lay on the ground, not underground. I installed another hose bibb. My neighbors asked what I was doing and I explained. Now, my neighbors usually follow my lead, but not this time. Their loss. These systems really only look intimidating to install.

System Maintenance
In the spring, I make minor repairs to damaged lines and broken drip fittings. I extend lines to new landscaped areas. Last year, I replaced part of the original pipe to the new tree because I damaged it with my snow blower. Stupid winter! In the fall, I remove the pressure reducers from the hose bibs, disconnect them from the the pipes, blow the water out of the pipes, and lay the pipes on the ground.

When I turn my system on, water flows to the emitters creating hissing sounds until the pipes fill. Then I hear the slow drips from the emitters. The streamjets will hiss normally. Any loud water flowing sound is cause for concern.

Incidentally, inspecting these systems is not within the scope of a buyer's home inspection. If buying a home with one, I recommend that you ask the homeowner for layout and operating instructions.  If they use an irrigation contractor for maintenance, ask the homeowner for their contact information. You can also look at the landscaping. Is it green and colorful? Then I would say that the system is working. Are there brown spots visible? Then there is probably an issue with the system.

For more general information on drip irrigation systems, you can visit Rain Bird online. This is not to be taken as an endorsement for their products, I have not personally used any, but this site has some neat information for homeowners including help "mapping" a new system custom to your yard. If you provide them with some information and measurements, they will design a system for you for free and send you the PDF plans--I haven't done it, as I said, but it looks interesting.