In the American Southwest, the two things a grower has most of are sunshine and distance. The water is often hundreds of feet underground, the nearest power line can be miles away, and the hottest, driest days are exactly when crops need water most.
That combination makes solar-powered borehole pumping one of the most practical irrigation upgrades available to orchards, vineyards, market gardens and small farms across Arizona, New Mexico, southern Nevada, west Texas, southern Utah and inland California. This post explains how these systems work, where they fit best, how to size one, and what to know about costs, incentives and water rules before you buy.
How a solar borehole irrigation system works
A solar borehole system has only a handful of parts, and none of them burns fuel:
Solar array → Pump controller → Submersible pump → Storage tank → Filter → Drip or sprinkler lines
The panels power a controller (ideally with MPPT and dry-run protection), which drives a submersible pump sitting in the well below the water line. The pump lifts water into a storage tank, and a float switch stops it when the tank is full. From the tank, water flows through a filter to the drip or sprinkler lines, by gravity or with a small booster pump. Because the tank holds the day's pumping, you can irrigate at dawn, at dusk or on cloudy days, whenever the crop needs it.
Why it fits the Southwest so well
Solar pumping works anywhere the sun shines, but the Southwest stacks the odds in its favor.
- Supply matches demand. Irrigation demand peaks in clear, hot summer weather, which is exactly when panels produce the most. The pump works hardest on the days the crop is thirstiest.
- Deep groundwater needs a submersible. Many wells in the region draw from aquifers far below the 7–8 m (about 25 ft) limit of a surface pump. A solar submersible pushes water up from depth without a generator.
- Distance makes the grid expensive. Running a new power line to a remote well can cost more than the solar array itself. Off-grid solar avoids line extensions, demand charges and utility bills.
- Diesel is a recurring cost and a chore. Generator pumps need fuel deliveries, oil changes and engine rebuilds. A solar pump has no fuel and few moving parts.
- Small water, steady water. Orchards, vines and vegetable plots under drip need modest, regular volumes rather than huge flood flows, which suits the output of a solar pump.
The main limitation is that a direct-drive solar pump only runs while the sun is up. In a USDA-funded project on Navajo farms in Arizona, growers found that direct pumping from their well was effectively limited to roughly 10 a.m. to 3 p.m. through the season (Tolani Lake Enterprises / NRCS report). Good design works around that window, as covered below.
Where it pays off: four kinds of growers
Orchards
Pecans, pistachios, stone fruit, citrus, olives and dates are long-lived trees with steady summer water needs. Drip lines or micro-sprinklers at each tree root zone deliver modest flows over long periods, which a solar pump and storage tank handle well. Pecan growers in New Mexico have already gone solar at farm scale, such as a Belen pecan farm that installed a $428,402 system with grant support.
Vineyards
Arizona's Willcox and Sonoita wine regions and New Mexico's vineyards rely almost entirely on drip. Vines need carefully controlled, often deficit, irrigation, so a system that delivers small, scheduled volumes is a natural fit. Solar also suits sites set on remote slopes away from existing power.
Market gardens
Vegetable and herb growers selling to farmers' markets, restaurants and CSAs typically farm one to ten acres under drip tape, often with shade cloth or hoop houses. Water needs are daily and predictable, and a single solar submersible feeding a tank can often cover the whole plot.
Smallholder and family farms
Small diversified farms, homesteads and tribal and acequia-area growers often sit far from three-phase power. One well-sized solar borehole system can irrigate crops, fill stock tanks and supply the household, all from the same tank.
Drip or sprinkler?
Drip is the better partner for solar in almost every Southwest case. It needs far less water and far less pressure, so a smaller pump and fewer panels can do the job.
| Drip / micro-irrigation | Sprinkler | |
|---|---|---|
| Typical operating pressure | Low (roughly 10–30 psi) | Higher (roughly 30–60+ psi) |
| Water lost to evaporation and wind | Very little | Significant in hot, windy afternoons |
| Solar array needed for the same area | Smaller | Larger, to supply pressure and volume |
| Best for | Orchards, vines, row vegetables, beds | Pasture, forage, lawns, frost protection, germinating seed |
| Works by gravity from a raised tank | Often, with pressure-compensating emitters | Rarely; usually needs a booster pump |
Sprinklers still have a place: pasture, alfalfa and other forage, germinating direct-seeded crops, and frost protection in some orchards. For those, plan on a larger array or a booster pump on the tank, and run sprinklers in the early morning to cut evaporation.
Sizing a system: five numbers to know
A solar pump is sized from the water side first, then the solar side. Gather these before you talk to a supplier.
- Daily water need. Gallons per day at peak season. Your county extension office or crop water-use (ET) tables can give a figure for your crop and acreage.
- Total dynamic head. The static water level in the well, plus drawdown while pumping, plus the height to the top of the tank, plus friction losses in the pipe. This, not well depth, decides pump size.
- Well yield. How many gallons per minute the well can sustain without running dry. Never size the pump above what the well can deliver.
- Peak sun hours. Much of the Southwest gets around 6–7 peak sun hours a day in summer. Daily water need divided by sun hours gives the flow rate the pump must hit.
- Storage. How many days of water you want on hand for cloudy spells and the monsoon season.
Store water, not electricity
The simplest, longest-lasting design pumps into an elevated tank or reservoir all day, then irrigates from the tank by gravity or with a small booster on any schedule you like. Water tanks are cheaper than batteries, last for decades and need almost no maintenance. Add batteries only when you truly need to pump at night or need steady pressure straight from the well.
Other design tips
- Choose a pump controller with maximum power point tracking (MPPT) and dry-run protection. It squeezes more water out of morning and evening light and protects the pump if the well draws down.
- Use a float switch in the tank so the pump stops when it is full.
- Consider single-axis tracking or a tilt that favors summer sun to stretch the daily pumping window.
- Size pipes generously; undersized pipe adds friction head and wastes panels.
- Fit filtration ahead of drip lines, since well water in the region can carry sand and minerals.
Recommended RockSolar kits for deep wells
Once you know your total dynamic head and daily water need, match them to a kit. Each RockSolar kit below pairs a DC brushless submersible pump and built-in controller with 445 W rigid solar panels, and carries a 5-year pump warranty. Pick a kit whose maximum head comfortably exceeds your total dynamic head.
| Kit | Max head (Kit A) | Flow (Kit A) | Solar panels | From |
|---|---|---|---|---|
| 0.8 HP Solar Submersible Pump + Solar Panel Kit | 290 ft | 15.6 GPM | 2 × 445 W | $1,199.99 |
| 1.34 HP Solar Submersible Pump + Solar Panel Kit | 326 ft | 17.4 GPM | 3 × 445 W | $1,899.99 |
| 1.61 HP Solar Submersible Pump + Solar Panel Kit | 391 ft | 17.4 GPM | 4 × 445 W | $1,999.99 |
| 2.41 HP Solar Submersible Pump + Solar Panel Kit | 574 ft | 16.1 GPM | 6 × 445 W | $2,499.99 |
| 3 HP Solar Submersible Pump + Solar Panel Kit | 782 ft | 15.9 GPM | 7 × 445 W | $2,899.99 |
| 4 HP Solar Submersible Pump + Solar Panel Kit | 1,050 ft | 16.9 GPM | 10 × 445 W | $3,799.99 |
Figures are for each kit's Kit A option; other options trade lift for higher flow, up to roughly 100 GPM on the larger kits for shallower settings. For a drip orchard or market garden on a moderately deep well, the 0.8 HP and 1.61 HP kits are a good starting point; the 2.41 HP to 4 HP kits suit very deep wells or larger acreage. Prices were current at the time of writing; check each product page for current pricing and availability.
Costs, payback and incentives in 2026
The upfront cost of a solar borehole system is higher than a diesel pump, but running costs are close to zero. Payback depends mostly on what you are replacing: displacing diesel fuel and generator maintenance usually pays back fastest, while avoiding an expensive power-line extension can make solar the cheaper choice from day one. Get quotes for the full system (pump, controller, array, mounting, wiring, tank and drip) and compare them with your current fuel or utility spend.
The incentive picture changed sharply in 2025–2026, so check current rules before you budget around any of them:
- USDA REAP (Rural Energy for America Program). A new final rule took effect on October 16, 2026. Projects must now be built and running for 12 months before you apply, and grants cover at most 25% of cost. Ground-mount solar on certified cropland is no longer eligible, so placement matters (summary of 91 FR 62600). REAP guaranteed loans remain available for upfront costs.
- NRCS EQIP (Environmental Quality Incentives Program). EQIP supports practices such as pumping plants, micro-irrigation, sprinkler systems, irrigation pipeline and irrigation water management. Sprinkler systems were among New Mexico's top EQIP practices in fiscal 2025 (NMSU / NRCS slides). Contact your local NRCS service center about ranking and deadlines.
- Federal business tax credit (Section 48E). Under the One Big Beautiful Bill Act, solar projects needed to begin construction by July 4, 2026 to keep the 30% credit on the older timeline; projects starting later must generally be placed in service by the end of 2027 (Jones Day). The residential solar credit (25D) ended after 2025. Talk to a tax adviser about your situation.
- State and utility programs. Some states, conservation districts and rural electric co-ops offer their own cost-share or rebates. Ask your extension office.
The safest approach is to build a business case that works with no grant at all, then treat any incentive as a bonus.
Check your water rights first
Cheap solar energy does not mean unlimited water. Groundwater in the Southwest is closely regulated, and many basins are already over-drawn.
- In Arizona, Active Management Areas and Irrigation Non-Expansion Areas restrict new irrigated acreage and well use.
- In New Mexico, the Office of the State Engineer administers groundwater permits, and many basins are closed or limited.
- Texas, Nevada, Utah and California each have their own groundwater districts, permits or sustainability rules.
Before drilling a new well or expanding irrigated acreage, confirm what your existing rights allow. Pairing solar pumping with drip, soil-moisture sensors and good scheduling helps you grow more with the water you are permitted to use.
The bottom line
For orchards, vineyards, market gardens and small farms in the sunny, deep-water Southwest, a solar submersible pump feeding a storage tank and drip system is reliable, low-maintenance and free to run. Size it from your water needs, store water instead of power, and build the numbers so the project stands on its own before counting on incentives.
Thinking about a system for your property? Gather your well depth, static water level, well yield, crop and acreage, and talk to a solar pumping specialist for a sized quote.
Sources
- Tolani Lake Enterprises: Navajo and Hopi Solar-Powered Irrigation Pumping Systems, NRCS CIG final report
- USDA REAP final rule summary, October 2026
- Jones Day: IRS guidance on wind and solar tax credits
- NMSU / NRCS New Mexico program slides, May 2026
- Los Alamos Daily Post: Belen Pecan Farm Goes Solar