Georgia's Watering Hours, and the Exemption That Matters Most

Every homeowner in metro Atlanta has heard there are watering rules. Rather fewer know what they say, and almost nobody knows about the exemption that makes a new landscape installation possible.

The rule

Georgia law permits outdoor irrigation for the purposes of planting, growing, managing or maintaining ground cover, trees, shrubs or other plants only between the hours of 4 p.m. and 10 a.m. The schedule was added to state law at O.C.G.A. 12-5-7 by the Georgia Water Stewardship Act of 2010, and counties and municipalities were required to adopt it by ordinance.

Two things about it are commonly misremembered. It is a daily schedule, not an odd and even day system. And it is a window of eighteen hours, not a restriction to a couple of hours, so in practice it rules out watering across the middle of the day and leaves everything else open.

That is not a hardship. Watering in the middle of a Georgia afternoon loses a substantial share to evaporation before it reaches the root zone, and most controllers here are set to run in the small hours anyway, which is when you would want them running regardless of the law.

The exemptions

The statute lists exemptions carrying no time limitation. The ones that matter for residential landscaping are:

• irrigation of new and replanted plant, seed or turf in landscapes, during installation and for 30 days immediately following the date of installation
• drip irrigation or soaker hoses
• hand watering with a hose fitted with an automatic cutoff, or with a handheld container
• personal food gardens
• water from a private well or from surface water on the property
• installation, maintenance or calibration of an irrigation system

The first one is the important one, and it is written into the statute precisely because establishment is the period when a plant cannot wait. A new install can be watered on the schedule the plants need for its first month, and after that the normal hours apply.

The drip exemption is the second most useful. A bed on drip irrigation can run at any hour, which combined with the fact that drip applies water slowly enough for clay to absorb it makes drip in beds the obvious choice on this ground rather than a premium option.

What it means for scheduling a project

Three practical consequences.

Installation date matters legally as well as horticulturally. The 30-day window runs from the date of installation, so a plant that goes in during a heat wave and a plant that goes in during a mild October both get the same allowance, and only one of them needs it.

Fall planting makes the window generous rather than tight. UGA Extension recommends fall for most woody plants and perennials in Georgia because irrigation demand is lower and root growth continues after dormancy. A plant installed in October needs materially less water through establishment than the same plant installed in May, which means the exemption is comfortable rather than barely sufficient.

Design the system to the law. A controller programmed to run inside the window from the day it is commissioned never has to be reprogrammed at the end of the establishment period, and nobody has to remember.

Watering clay, whatever the hour

The legal question and the technical question are separate, and the technical one catches more people out. The Metro North Georgia Water Planning District puts practical clay absorption at up to about half an inch of water per hour. A typical spray zone applies considerably more than that, so within a few minutes the surplus is running across the surface rather than soaking in, and on a sloping lot it goes downhill taking mulch with it.

The fix costs nothing. Split each zone into two or three shorter cycles with soak time between them. The same total volume goes on, none of it runs off, and it works on an existing system with no hardware change at all. That single adjustment is the most effective improvement available to most irrigation systems in this city.

And whether the system is needed

NOAA’s 1991 to 2020 normals for the Atlanta area record just under 50 inches of precipitation a year, spread across about 113 days with measurable rain, and July is the wettest month. Established planting on a sensible palette rides out most summers here without irrigation.

Where a system earns its keep is through establishment, and on lawn, which has no strategy for drought beyond going dormant. Plenty of properties in Sandy Springs are best served by drip in the beds, a system on the lawn, and nothing at all in the woodland areas. That is cheaper to install and cheaper to run, and it sits comfortably inside both the law and the soil.

More on system design and the rest of the rules in the irrigation guide.

Sources: O.C.G.A. 12-5-7 as added by the Georgia Water Stewardship Act of 2010. Metro North Georgia Water Planning District irrigation guidance. NOAA 1991 to 2020 climate normals for Atlanta Hartsfield-Jackson. UGA Extension Circular 873.