The three phases
| Phase 1 — Water | Drilled well (licensed New Mexico driller), solar pump, storage, buried distribution line |
|---|---|
| Phase 2 — Septic | Site evaluation, permitting, tank and disposal field set to required setbacks |
| Phase 3 — Power | Off-grid array, battery and inverter package, ground-mount racking and concrete |
| Runs throughout | Permitting and inspections, subcontractor scheduling, material procurement, site access |
The order is not arbitrary. Water comes first because it carries the most uncertainty — nobody knows what a well costs until it is drilled — and because downstream decisions, including where the septic system can legally sit, depend on where the well lands. Power comes last because it is the phase you can plan precisely once the layout is settled.
Phase 1 — Water
A licensed New Mexico well-drilling contractor drills the well; we manage the schedule and carry the rest of the water scope. Depth is the variable nobody can promise, so we price to a target depth and quote the per-foot rate beyond it. On our Torrance County system: a 200-foot well with 6-inch steel casing, priced to 200 feet, additional depth billed at $75 per foot.
Getting water out of the ground is only half the phase. The rest is a pump and the power to run it, storage that decouples supply from household demand, and buried distribution. On that project: an RPS 800 helical-rotor pump on a dedicated 1,200 W array with an MPPT boost controller and generator auto-switch, feeding two 2,500-gallon NSF-61 cisterns through roughly 520 linear feet of 1.5-inch HDPE buried at a minimum of 30 inches, with the water line inspected under New Mexico CID jurisdiction.
Budget realistically for trenching. Rocky ground is common across central New Mexico and it is the line item most likely to move: trenching runs by the day, and the ground decides how many days.
Phase 2 — Septic
Septic is the phase that surprises people, because site conditions and setbacks govern it rather than preference. Tank and disposal field placement is constrained by required separation from the well, the building site, and property lines — which is exactly why it belongs after the well is in and before anything permanent is placed.
The work runs on its own review timeline: site and soil evaluation, permitting, then installation and inspection. No contractor compresses that calendar, so the practical move is to start it early and let it run alongside work that does not depend on it.
Phase 3 — Power
Power lands last because by then the layout is known: where the structure sits, where the well and pump are, where equipment can be reached for service. A full build means an array sized to real loads, a matched battery and inverter package, and — on open land — ground-mount racking anchored in concrete, which brings excavation and cure time with it.
Our 2026 central New Mexico build is a fair reference for scale: 14.4 kW DC on ground mount, battery and inverter package, roughly four weeks from mobilization to a live system. On installs of that kind, equipment is roughly two-thirds of the cost and labor plus site work is the balance — worth knowing before comparing bids, since the battery bank is the easiest item for a cheap quote to shrink.
What one contractor changes
- The sequence has an owner. Split across three contracts, the gaps between phases belong to the land owner. Combined, the handoffs are ours to schedule.
- Site work stops being duplicated. Trenching, access, and heavy equipment mobilization can serve more than one phase when the phases are planned together. Separate contracts mean separate mobilizations, each one billed.
- Layout gets decided once, with everything on the table. Well placement, septic setbacks, array location, and service access all constrain each other. Deciding them together avoids discovering in phase three that phase one took the ground you needed.
- Permitting runs in parallel, not in series. Different approvals move on different calendars through different jurisdictions. One schedule is how the slow ones start early instead of becoming the critical path.
What to budget
We do not publish a package price, because well depth alone can move a budget before anyone touches the solar design. What we can give you is scale from real 2026 contracts: the Torrance County water system ran about $55,000 and the 14.4 kW off-grid solar build ran about $62,500. Systems like these have run $55,000–$62,500 — but each was a single discipline rather than a combined package, so a property needing all three phases gets scoped as its own job.
Two planning notes: the federal Section 25D residential credit terminated December 31, 2025, and New Mexico allows a gross receipts tax deduction on the sale and installation of solar systems under NMSA 1978 § 7-9-112 — confirm your contractor handles that paperwork.
Where these go sideways
Most trouble on these projects is scheduling, not technical. It takes three forms.
- Permitting started late. Reviews run on their own calendar. Filing when the crew is ready is filing weeks too late.
- Material ordered without regard to phase order. Long-lead equipment arriving out of sequence means either storing expensive hardware on an open site or a crew waiting on a truck.
- Concrete scheduled into monsoon season. Cure time sits directly between site work and everything visible, and New Mexico summer afternoons are reliably stormy. Move the pour rather than gamble on a dry day.