Outside Monticello city limits nearly every irrigated lawn we maintain runs off a well. That changes a few things: how much water you can put out at once, what that water does to the house and the driveway, and how the whole system should be scheduled. Get it right and a well is a cheap, reliable water supply. Get it wrong and you burn out a pump.
The pump sets the rules
A municipal connection delivers roughly steady pressure and flow all day. A well delivers whatever the pump can push, and no more. A typical residential well pump moves somewhere in the range of eight to fifteen gallons a minute at usable pressure, which is enough for a limited number of sprinkler heads at once. Put too many heads on one zone and every head runs weak, the far end of the zone gets almost nothing, and the pump runs at the top of its curve trying.
The practical rules:
- Know your pump's flow. Time how long it takes to fill a five-gallon bucket from a hose bib with nothing else running. That number, in gallons per minute, is what the zones have to fit inside.
- Size zones to the pump, not to the yard. More zones, fewer heads each. A zone that runs weak needs to be split.
- Do not run two zones at once, and do not run the irrigation while the house is drawing water for laundry or showers.
- Give the pump rest. Long run times are better for a pump than short, frequent cycles. That happens to match how a lawn should be watered anyway.
Our post on auditing a sprinkler system covers how to find the weak zones and the broken heads.
Iron and the orange stain
Much of the groundwater in the Big Bend carries dissolved iron. It is invisible coming out of the head, then oxidizes on contact with air and leaves an orange-brown stain on anything it dries on: siding, fences, sidewalks, the driveway, the mailbox post. It is harmless to the lawn. Centipede actually likes a little iron. It is a problem for the house.
What helps:
- Adjust heads so no spray reaches the house, the fence or the concrete. Half-circle and quarter-circle nozzles along edges, and a check that the throw is not being carried by wind.
- Water in the early morning so anything that does land on a surface is diluted by dew and dries slowly rather than baking on.
- Clean stains early with a product made for rust removal on the surface in question. The longer they sit, the harder they are.
- Consider a treatment system if staining is severe. Injection systems that keep iron in solution, or a filter, are available for irrigation wells, but they are a real cost and worth pricing against just adjusting the heads.
Sulfur and hardness
Some wells south of town toward the coast carry a sulfur smell, which does nothing to the lawn. Hardness, dissolved calcium and magnesium, can leave white deposits on surfaces and over many years nudges soil pH upward. On a centipede lawn, which wants acid soil, that is worth watching. A soil test every couple of years through your county extension office catches it, and our soil testing post covers how.
Scheduling a well-fed system
The lawn's needs do not change because the water comes from a well: deep and infrequent, a half inch to three quarters per application, two or three times a week in dry weather and not at all in a wet one. What changes is how you get there. Because each zone is pushing less water, run times are longer. Measure with catch cans on each zone to find how long it takes to put down a half inch, and set the controller to that number. Run one zone at a time, starting early enough that the whole cycle finishes by mid-morning. A rain sensor is worth having; see our post on rain sensors and controllers.
Drought and the well
In a hard dry spring the water table drops, and a shallow well can lose pressure or pump air. If the pump starts cycling or the pressure fades during a run, stop. Running a pump dry ruins it. Let the well recover and water fewer zones per day until the rains return. This is one more argument for a lawn that has been watered deeply and has roots that can wait.
FAQ
Is well water bad for the lawn?
No. The iron, sulfur and minerals in Big Bend well water are fine for turf. The issues are the house and the pump.
Why is the far end of my zone always dry?
Too many heads for the pump's flow. Split the zone or reduce the nozzle sizes.
How often should I run the well for the lawn?
As often as the lawn needs, which is not every day. Deep and infrequent is easier on the pump as well as the grass.
Do you audit irrigation on well systems?
We look at coverage and scheduling as part of setting up a maintenance plan, and we'll tell you when a zone needs a repair.
If your pump runs all night and the lawn is still dry, get in touch and we'll look at the zones. We maintain irrigated lawns on wells all over the county, from Waukeenah to Ashville.