The default residential irrigation system in San Antonio is pop-up spray heads running on a fixed timer, watering a lawn in the early evening. Almost every part of that sentence is wrong. The spray loses 30 to 50% of its volume to evaporation in summer. The fixed schedule waters whether it rained yesterday or not. The early-evening start leaves foliage wet overnight and runs disease pressure straight up.
You can do better — and you can usually do it on less water. The selection rules below are the ones we use on every Noon build.
Why spray loses water.
A spray head throws water through the air in a fan or arc. In San Antonio summer — afternoon temperatures pushing 100, relative humidity often below 30%, wind gusting from the south — somewhere between 30% and 50% of that water evaporates or drifts before it ever touches soil. Run a spray system at 4 PM in August and you can lose half the cycle volume. Run the same cycle at 4 AM and you cut the loss to under 10%.
That is before you account for the rest of the spray pathology: water lands on leaves and stems where it does no good and promotes disease, water bounces off compacted soil and runs to the gutter, water lands on the sidewalk because the head is misaligned. Spray is the highest-loss delivery method in residential landscape, period.
Why drip drives deeper roots.
Drip emitters deliver water at the soil surface, slowly enough that it infiltrates instead of running off, and exactly where the plant needs it. Three things follow:
- No evaporation loss in the air. Every gallon you turn on reaches the soil.
- Deeper infiltration. A long, slow drip cycle pushes moisture 8 to 12 inches down into the profile. Plant roots follow the moisture. Deeper roots mean drought tolerance, structural anchoring, and a plant that survives the next dry stretch without supplemental water.
- Dry foliage. Disease pressure drops sharply when leaves stay dry.
Drip uses roughly 30 to 50% less water than spray for the same plant-level result. In a tiered SAWS rate environment that is a direct annual cost reduction on top of the plant-health benefit.
The Noon stack — what we put where.
Garden beds, perennial beds, foundation plantings, vegetable beds: drip. Inline emitter tubing on 12 to 18 inch spacing, 0.6 to 0.9 GPH emitters, run under 2 to 3 inches of mulch. Pressure regulator at the zone valve (drip wants 20 to 30 PSI). Filter at the valve.
Vegetable beds, dense plantings, container clusters: microspray, sometimes. Low-volume microspray heads (5 to 15 GPH, 1 to 2 foot throw) work for tightly planted bed sections where individual drip emitters are impractical. Same pre-dawn schedule. Same pressure regulation.
Native grass meadows and recovering pasture during establishment: rotor sprinklers, briefly. A meadow planting that needs uniform moisture across a wide area during the first 6 to 12 months of establishment is a fair use case for rotor heads. After establishment, the rotors come off the schedule. Native grasses do not want supplemental irrigation past year one — watering a mature native meadow is how you invite Bermuda and Johnson grass in.
Lawn: nothing. If the lawn is St. Augustine or another high-water turf, the right move is to shrink it, not to irrigate it. If the lawn is buffalo grass or a native-grass blend, it does not need supplemental water past establishment. Spray heads on a residential lawn are the irrigation choice we replace most often.
Watering windows — the only window that works.
Pre-dawn. Between roughly 3 AM and 7 AM, depending on your zone count and run times. Three reasons in this order:
- Air is cool, evaporation is minimal, the soil gets the water.
- Foliage dries off as the sun comes up — fungal pressure stays low.
- You are not running the system when you are using water inside the house, which protects pressure and emitter consistency.
Howard Garrett has been saying never water at night for thirty years. He is right. Night watering leaves leaves wet for 8 to 10 hours and runs disease pressure straight up. Afternoon watering is even worse — you pay for water that evaporates before it does any work. Pre-dawn is the only window that respects the plant and the meter at the same time.
Frequency — deep and infrequent always wins.
One long cycle every 10 to 14 days beats five short cycles a week, every time. The reason is root architecture. A plant watered shallowly every day forms a shallow root mat — it never has to reach deeper because the moisture never gets there. A plant watered deeply and infrequently sends roots down to chase the moisture profile, and those deep roots are the difference between a plant that survives the next August and a plant you replace.
For drip-irrigated bed plantings in San Antonio summer, our standard schedule is roughly:
- Established native shrubs and perennials: 1 cycle every 10 to 14 days, 60 to 90 minutes
- Established native trees: 1 cycle every 14 to 21 days, 2 to 4 hours
- Vegetable beds in production: 2 to 3 cycles per week, 30 to 45 minutes
- First-year establishment plantings: 2 cycles per week, 45 to 60 minutes, tapering through year one
A smart controller adjusts these against rainfall and ET (evapotranspiration) data automatically. That is the controller's whole job, and it is worth doing right.
Smart controllers — worth installing.
A weather-based smart controller (Rachio, Hunter Hydrawise, Rain Bird ESP-TM2 with the LNK module, B-hyve) pulls local rainfall and ET data and skips or shortens cycles when the plants do not need the water. Compared to a fixed-schedule timer, smart controllers typically cut landscape water use 20 to 40%. The unit pays back inside two summers on most properties.
The setup matters. A smart controller running zones that were sized wrong, or running spray and drip on the same program, will not save you anything. The right install is: each zone profiled (plant type, soil type, slope, sun exposure), drip and spray on separate programs, rainfall skip threshold set conservatively, and one annual walkthrough to catch broken emitters and misaligned spray heads.
Gray water — the bonus water.
Texas allows residential gray water reuse without a permit up to 400 gallons a day, for subsurface irrigation only. Shower, bathroom sink, and laundry water can route through a simple branched drain system to drip lines under mulch in the landscape. For a family of four that is roughly 80 to 120 gallons a day of free irrigation water, enough to water a substantial perennial garden or several fruit trees through summer.
Gray water is best on fruit trees, ornamentals, and non-edible perennials. Not on root vegetables, leafy greens, or anything eaten raw. Detergent choice matters — biocompatible, low-sodium, low-boron soaps only.
For more on how irrigation system sizing ties into rainwater catchment and overall water budget, see Rainwater Harvesting for San Antonio Homes.
The drip layout — for a bed.
A standard Noon drip install for a 200 sqft perennial bed:
- 3/4-inch poly mainline from the zone valve to the bed
- Pressure regulator at the bed inlet (25 PSI)
- Y-filter at the bed inlet (150 mesh)
- 1/2-inch inline emitter tubing run in serpentine pattern across the bed, lines on 12 to 18 inch spacing
- Emitters at 12-inch spacing along each line, 0.9 GPH each
- Flush cap at each line terminus
- Whole layout buried under 2 to 3 inches of shredded hardwood mulch
That layout, run for 60 minutes once every 10 to 14 days in summer, keeps an established native bed alive on roughly 350 to 500 gallons per cycle — somewhere between a third and a half of what the same bed would draw under a spray system on a daily schedule. The plants come out healthier and the SAWS bill comes down at the same time.