The 50% plant coverage rule, explained.
To qualify for the rebate, plants must cover at least half of the converted area — measured at the plants' full-grown size, not their size on planting day. This one rule causes more failed applications than anything except removing grass too early. People plan by what looks right today, and the rule measures what the yard becomes.
How does the math work?
Every plant has an expected full-grown width. A desert willow spreads about 25 feet across — that counts as about 490 square feet of coverage from one tree. A red yucca spreads about 3 feet, or about 7 square feet. If you convert 2,000 square feet of lawn, you need 1,000 square feet of coverage. For example:
- 1 desert willow (490) + 2 Texas mountain laurels (about 113 each) + 8 Baja fairy dusters (about 28 each) + 10 red yuccas (about 7 each) ≈ 1,032 sq ft ✓
- …or 40 small one-gallon shrubs spread around the yard ≈ 300 sq ft ✗ — it looks planted, but it fails the inspection.
Two things follow from that first list. Trees do most of the work, and each new tree also adds $100 to your rebate. And a yard that passes this rule usually looks much better than the lawn it replaced, because the rule forces a real landscape design.
Three details people miss
- Overlapping plants do not count twice. If two full-grown plants would overlap, the shared area counts once. Space them apart when you plan.
- The plants must be alive at the final inspection. Planting in the Las Vegas summer is risky. Fall planting is much safer.
- Every counted plant must be on drip irrigation, with a filter and pressure regulator in the line. The inspector checks.
Start with your rebate number, then plan the plants against it. If you would rather not do the math yourself, a licensed contractor's plan comes with the coverage already calculated.
Requirements summarized from public SNWA program rules; verify current terms at snwa.com. Not affiliated with any water district.