Don’t Fear Your Irrigation System – Basic System Layout Explained

I’ve had homeowners paralyzed with fear, unwilling to make changes to their landscape because of the terror that lurks below the surface. No, not Tremors (though that may be some of Kevin Bacon’s finest work) – their irrigation system. Once you know how your system works, it really isn’t that terrifying.

Irrigation System Design Basics

Here’s a basic diagram of an irrigation system layout:

Some homeowners are terrified to even bump against an irrigation line. Folks, it’s not a water main. The valves have to be on before water flows through the lines.  Let’s follow the water through your irrigation system:

Step One: The backflow preventer


Where the irrigation system taps into your household water supply, code requires a backflow preventer. This prevents anything in the irrigation system water (dirt, sand, garden chemicals) from flowing back in and mixing with your tap water. This valve is sometimes located in the basement, sometimes outside.

Step Two: Main shutoff valve


Every system should have one. If yours doesn’t have a main shutoff valve, that’s worth a call to get one installed. Often they’re located at the backflow preventer, but not always. Even if your backflow preventer has a shutoff valve, if the backflow is in the basement you should have a shutoff valve outside.

Step Three: The main line

Your irrigation system will have a main feed line that runs from the house to the valve manifold. This line is always charged (has water running through it), which is why a system shutoff valve is so important. If you break the main line, it’s the part of the system that will stream water until it’s shut down.

Step Four: The valve manifold


Water flows to the valve manifold and stops until the appropriate valve is opened. Each zone on your controller has its own valve, so when your front shrub zone comes on, that valve opens and water flows to the zone until the controller closes the valve again.

Step Five: The individual zones


When the valve opens, water fills the pipes in that zone and comes out the sprinkler heads (or drip tubes, or flood bubblers – whatever’s at the end of the line). When the valve closes, there’s no longer pressurized water in that zone, although you may have water dribbling out of the lowest head in the system for a few minutes. That’s just gravity and is perfectly natural.

As you can see, irrigation systems are very straight forward to understand and not at all terrifying. You may still want to have a professional service your system (and I strongly recommend a pro to install your system), but at least now you know how your system works – and that you’re not going to blow up the world if you nick a line).



Formal Water Features in Landscape Design

Sometimes you want to wear flip flops and shorts, and sometimes you want to rock a more classic look. Formal water features never go out of style!

Gene Kelly is ALWAY classy.

Your garden feels the same way. How about some formal fountain ideas?

formal water features

Here’s a classic fountain. Concrete basin, carved stone or precast coping, and a statue. Very old school formal.

formal water features

The formal geometry of this fountain gives it formality. So does the way it sits in a very formal geometrically laid out garden, which unfortunately doesn’t really show in this photo.

formal water features

Reflecting pools? Almost always formal. This one sure is.

Don’t think that you have to live on a palatial estate with some grand home with turrets and a mansard roof to pull off a formal water feature. A formal fountain can be a great way of pulling some of the structure of the house way out into the garden. We design custom water features for our clients (like this Oakton Virginia water feature!) but you can also get a great deal on a fountain or water feature here. This is an affiliate link; I may get a commission if you buy from them. 


Using Dry Stream Beds for Drainage

Here in Virginia we have clay soils that don’t drain particularly well. We also get a fair bit of rainfall. When new subdivisions are built, especially in northern Virginia, the county-mandated drainage plan often moves water through everyone’s backyards towards a county storm drain. If you have a newer home, you may even have a legally designated stormwater easement on your survey plat.

What this means is that for many homeowners, you’re likely to have a fair bit of water moving through your yard during a storm event. When you moved in, the builder had probably sodded your backyard, and well-established grass stands up reasonably well to a decent volume of water moving across it.

Sometimes grass isn’t an option, though. Maybe trees have grown up and grass will no longer grow, and you’re experiencing erosion. Maybe your new patio or plant beds mean that water needs to be diverted. Or, as was the case for these folks, the slope was so steep that keeping the grass cut was a miserable experience.

So, the decision was made to turn the area in front of the downhill fence into a planting bed. Having all your mulch washed into a pile against the fence is never fun, so I looked at where the swale was most pronounced – this is where the water was flowing – and built a dry creek bed to carry the water.

We also used a number of plants to help hold the slope, including winter jasmine, cotoneaster, and pachysandra. As the birch trees grow up and fill out, this will be a nice little oasis in suburbia.

Fighting nature is hard. Working with it – whenever you can – is the better choice.