Penn State's Center for Sports Surface Research keeps the best published temperature data on synthetic turf, and the highest figure in it was taken in Utah. On a 98 degree day in Provo, synthetic turf reached 200 degrees Fahrenheit. Their central Pennsylvania maximum, measured six years later, was 175. Across their work, synthetic turf generally runs 35 to 55 degrees hotter than natural grass, which on a hot day sits between 75 and 95 degrees and rarely exceeds 100, because transpiration cools it.
Provo is not St. George. St. George recorded 98 days at or above 100 degrees in 2024, with an all time high of 117 degrees, set in July 1985 and matched in July 2021. The 200 degree measurement was taken at 98 degrees ambient, which makes it a floor for this market rather than a ceiling. That is the honest starting point for the conversation, and it is not the end of it, because there are places where turf is still the right call.
The watering rebound
The obvious answer to a hot surface is to wet it, and that has been tested. In work run at Brigham Young University and reported inside the Penn State research, thirty minutes of irrigation brought a synthetic turf surface down to the temperature of the natural grass beside it, about 85 degrees. Within five minutes it had rebounded to 120. Penn State's own published figure for how long watering helps is a reduction of as much as 20 degrees an hour and a half later.
Read those two results together and the water argument gets thinner. If the surface needs irrigating to be usable on a July afternoon, then a product bought to eliminate irrigation is being irrigated. It is still using far less water than a lawn. But it is not the zero it was sold as, and the cooling it buys is measured in minutes, not afternoons.
The practical version for a homeowner: plan for a surface you will not walk on barefoot in the middle of a summer day, and do not plan on hosing your way out of that.
Where turf is the right answer
There are four situations where we will recommend it without hedging.
Small areas in real shade. The Water Conservancy District's own urban heat material makes the point that shade trees can lower surface temperatures by up to 50 degrees, and that shading keeps areas up to 25 degrees cooler. Shade beats material choice by a wide margin. Turf under an established canopy is a different product than turf in open sun.
Strips where lawn is not legal anyway. St. George City Code § 10-7-7 caps residential lawn at 8 percent of lot size with a maximum of 1,500 square feet, and prohibits lawn outright in park strips, in any landscape area less than eight feet wide, and on slopes over 15 percent. A four foot side yard is never going to be grass. The choice there is between turf, mulch, gravel and pavers, not between turf and a lawn.
Dog runs and small use areas where the alternative is bare dirt. And places where the surface has to take traffic that would kill a planting in the first season.
In each of those cases the deciding factor is the same: the area is small, it is shaded or it is not walked on barefoot at two in the afternoon.
How the rebate treats it, which is not how most people assume
This is the part that surprises people. Under the Washington County Water Conservancy District's program, artificial turf is accepted in lieu of mulch if it is permeable to air and water. The District's own answer to whether there is a rebate for replacing lawn with artificial turf is, verbatim, not exactly, but you may use artificial turf as a component of your project.
In lieu of mulch is the whole sentence. Turf is treated as a ground covering, not as a landscape. It does not count toward the living plant coverage the program requires, and the plants still have to be there. The District's agreement sets the depth for the ground covering generally: at least 2 inches of mulch, with permeable artificial turf named as one of the acceptable materials.
Permeability is also doing real work in that rule, and not only for the rebate. The District's urban heat material identifies impermeable surfaces, streets, sidewalks and buildings, as the main contributors to urban heat because they absorb and release it, raising nighttime temperatures. What goes down on the ground affects the air over it.
One municipal caveat the District's rule does not reach. Toquerville City Code § 10-21A-5 says "Synthetic turf is not permitted as a substitute for planting materials." The water district accepts permeable artificial turf in lieu of mulch; Toquerville city code does not accept it as a substitute for planting. At a Toquerville address the District rule is not the whole story, and the city code has to be read before anyone specifies turf.
| Surface | Counts inside the rebated area? | Note |
|---|---|---|
| Permeable artificial turf | Yes, in lieu of mulch | District program only. Must pass air and water |
| Ungrouted pavers, dry set flagstone | Yes, treated as mulch | Grout defeats permeability and the credit |
| Decomposed granite, gravel, rock mulch, bark | Yes, it is mulch | The ordinary case |
| Poured concrete | No, subtracted | The District subtracts non-permeable areas when calculating the incentive |
| Mortared or grouted paver and flagstone | No, subtracted | Same reason as concrete |
| Pool, pond, water feature | No | Also prohibited in the conversion area by the recorded easement |
| Bare soil | Only for native desert restoration | The program agreement and Standards §5.D allow it where native plants restore an area to native desert; the easement's Exhibit B does not carry the exception |
The state program takes the opposite position
Worth knowing if you have been reading around. Utah's statewide landscape incentive program excludes artificial turf outright: its definition of water efficient landscaping does not include artificial turf, a swimming pool, water feature or concrete. Utah Water Savers explains why in its own FAQ, saying research has shown that artificial turf can cause much more environmental harm than it can offset by its water saving potential.
In Washington County the district program is the one that applies, because the state's own eligibility page routes every Washington County jurisdiction to the district, which is why these are best understood as one program administered locally rather than two you could stack. Confirm that with the district before you plan around it. So the District's permeable in lieu of mulch rule governs a conversion here. But the disagreement between two state level water agencies is a fair thing for a homeowner to weigh, and pretending it does not exist would be the wrong way to sell anything.
What fails on turf in this climate
The fiber is usually not what goes. The backing and the infill degrade under ultraviolet and thermal cycling, and the backing typically fails before the surface looks worn out. That is the same failure pattern that takes out exposed plastics generally here: irrigation boxes, exposed poly tubing, plastic edging, sealants and caulks all embrittle or crack under this ultraviolet load faster than manufacturer literature written for other climates implies.
Two consequences for a specification. Ask what the backing is warranted for in a high ultraviolet, high temperature installation, and read the temperature exclusions rather than the headline year figure. And treat the drainage under it as real construction rather than as a mat on dirt, because a permeable surface over compacted subgrade is not permeable in any way that matters when the first August cell arrives.
What planted conversion does instead
The rebate program requires 50 percent living plant cover at maturity across the converted area, and the way the District measures it is more generous than most people expect. Mature size is what counts, not the size at installation. Trees are credited at 350 square feet of cover each and shrubs, groundcovers and other perennials at 35 square feet each, which makes one tree equal to ten plants. Existing trees and plants in the lawn area that survive the conversion are applied to the calculation, and the District specifically lists you must remove your trees as a myth it is debunking.
Do the arithmetic on a 1,000 square foot conversion. You need 500 square feet of mature cover. Two trees is 700. One tree plus five shrubs is 525. Fifteen shrubs and perennials is 525. That is a real planting, not a token one, and it is achievable without covering the ground in vegetation.
The trees are doing the heavy lifting on heat, which is the point of this whole page. The District's own material says shade trees are far more effective at cooling temperatures than grass, with the potential to lower surface temperatures by up to 50 degrees, and that grass uses four times more water than trees and shrubs. St. George City Code § 10-7-7 separately requires two water conserving trees at each single family dwelling, at a minimum one and one half inch caliper, and § 10-23-3 requires at least one of them in the front yard. The District publishes its own top ten list to choose from, including Chinese Pistache, Desert Willow, Texas Red Oak, which its notes describe as well adapted to our alkaline soils, and Mondell Pine.
One thing we tell every customer before they sign anything. Low water is not no maintenance, and the District says so in its own materials. A planted conversion needs pruning, emitter checks and weed control, and the first three years are the ones that decide whether it looks like the rendering. Anyone who tells you a xeriscape is finished on install day has not maintained one.
The way we would decide it
Look at the area in question at two in the afternoon in July and ask three questions. Is it shaded. Will anybody stand on it barefoot. Is it small.
Three yeses and turf is a sensible product used the way the District treats it, as a ground covering that does not need irrigation. A no on shade and a yes on foot traffic, and you are buying a surface you cannot use during the months you are most likely to want it. In that case the money goes further in trees, and the trees keep working on the house behind them.
What we’d do at your house
We walk the area with you in the sun and tell you honestly which parts of it are shaded enough for turf and which are not.
Where lawn is prohibited by the eight foot rule or the slope rule, we lay out the real options rather than defaulting to plastic.
At a Toquerville address we read the city code before specifying turf at all, because § 10-21A-5 does not permit synthetic turf as a substitute for planting materials even though the water district accepts it in lieu of mulch.
If turf is going in, it goes in permeable and over drainage we actually built, because that is what the rebate rule and the ground both require.
We do the plant cover arithmetic in front of you, with mature sizes and the tree credit, so you can see how the 50 percent is met.
We will tell you where the state program and the district program disagree about turf rather than quoting whichever one suits the sale.
We explain the recorded conservation easement before you commit to the conversion, not after.
Sources
What this page says comes from the documents below, read in full. It describes them. It is not legal advice. Confirm with your association, your city, or an attorney before you act.
- Penn State Center for Sports Surface Research: 200F on a 98F day in Provo (Williams and Pulley 2002); 175F Pennsylvania maximum (McNitt et al 2008); 35 to 55F hotter than natural grass; natural grass 75 to 95F; the watering rebound from 174F to 85F to 120F in five minutes and the three hour ten degree finding 05-environment-water-geology-corpus.md §3.6; 02-landscape-hardscape-corpus.md §5.7; playbook.txt §4
- St. George heat record: 98 days at or above 100F in 2024, all time high 117F 05-environment-water-geology-corpus.md §3.1; 02-landscape-hardscape-corpus.md §5.7
- WCWCD Urban Heat FAQ: impermeable surfaces as the main contributors to urban heat; shade trees lowering surface temperatures by up to 50 degrees; grass using four times more water than trees and shrubs 02-landscape-hardscape-corpus.md §5.7, §1.4
- WCWCD FAQ: shading keeps areas up to 25 degrees cooler 02-landscape-hardscape-corpus.md §1.4
- WCWCD FAQ on artificial turf and on concrete, and the permeable versus impermeable rebate calculation table 02-landscape-hardscape-corpus.md §2.4, §5.1
- Utah Water Savers and Division of Water Resources exclusion of artificial turf, and the stated reason 02-landscape-hardscape-corpus.md §2.4
- Utah Water Savers eligibility routing for Washington County, read alongside the district's own program terms 02-landscape-hardscape-corpus.md §2.1; briefs.txt §0 finding 3
- 50 percent living plant cover measured at maturity; 350 square feet per tree and 35 per shrub; existing trees count; the tree removal myth 02-landscape-hardscape-corpus.md §2.3
- Conservation easement prohibitions inside the conversion area; bare soil permitted only where native plants restore an area to native desert (program agreement and Standards §5.D), which Exhibit B of the easement does not carry verify/rebate-and-ordinances.json, retrieved 2 Sept 2026; 02-landscape-hardscape-corpus.md §2.4, §5.1
- St. George City Code § 10-7-7 (Landscape Standards, Residential Zones): lawn caps, park strip and eight foot prohibitions, 15 percent slopes, two water conserving trees at 1½-inch caliper; § 10-23-3 for the front-yard tree verify/rebate-and-ordinances.json, stgeorge.municipal.codes, retrieved 2 Sept 2026; 05-environment-water-geology-corpus.md §6.4
- WCWCD Most Wanted Trees list and species notes 02-landscape-hardscape-corpus.md §1.3
- Low water is not no maintenance, in the district's own words 02-landscape-hardscape-corpus.md §7.1
- Ultraviolet degradation of turf backing and infill, exposed plastics and sealants 02-landscape-hardscape-corpus.md §5.7; 05-environment-water-geology-corpus.md §3.5
- Toquerville City Code § 10-21A-5, Landscaping Guidelines: "Synthetic turf is not permitted as a substitute for planting materials." verify/rebate-and-ordinances.json, retrieved 2 Sept 2026
- WCWCD Water Efficient Landscape Program agreement: at least 2 inches of mulch, permeable artificial turf named as an acceptable material verify/rebate-and-ordinances.json, wcwcd.gov/welpagreement, retrieved 2 Sept 2026