What a complete system actually includes
The deliverable on off-grid land is not a pump on a pallet. It is water at the tap at six in the morning in February. That takes several pieces working as one system, and the specification below is a real one — a full water package we installed in Torrance County in July 2026, on raw land with no utility power at the property line.
| Well | 200 ft deep, 6 in. steel casing |
|---|---|
| Drilling | Performed by a licensed New Mexico well driller, subcontracted and managed by us |
| Pump | RPS 800 helical-rotor solar pump |
| Pump power | Dedicated 1,200 W solar array with MPPT boost controller |
| Backup | Generator auto-switch |
| Storage | 2 × 2,500-gallon NSF-61 cisterns (5,000 gallons) |
| Water line | 1.5 in. HDPE, NSF-61 rated |
| Trenching | Roughly 520 linear feet, rocky terrain, minimum 30 in. depth |
| Inspection | Water line inspected by the NM Construction Industries Division |
| Contract | About $55,000 as of August 2026; 70% deposit, 30% at completion |
We write the drilling line the way we do on purpose. The well on that job was drilled by a licensed New Mexico well driller working as our subcontractor, with the project managed end to end by us. We do not hold a drilling license and we do not claim one.
The pump is the least expensive part
Owners usually start the conversation at the pump, because that is the part with a model number. On a from-scratch water system the pump is a small share of the money. The well, the storage, and the trench are where the budget goes, and two of those three are priced by the foot or by the day because nobody — including the driller — knows exactly what the ground holds until the bit is in it.
| Complete solar well system (Torrance County scope above) | About $55,000 |
|---|---|
| Drilling beyond 200 ft | $75 per foot |
| Trenching | $1,300 per day |
| Payment structure | 70% deposit, 30% at completion |
That is why our quotes fix a base depth and publish the per-foot rate past it, rather than quoting one number and revising it after the rig is on site. On rocky ground the trench is the other variable. The Torrance line ran about 520 linear feet through rock at a minimum depth of 30 inches, billed by the day, and that single line item moves more dollars than the choice between two pump models ever will.
Why a helical-rotor pump
A helical-rotor pump — the RPS 800 on that job is one — is a positive-displacement design. It moves a fixed volume per rotation instead of relying on impeller speed, so it produces steady flow at modest input power and keeps working as the array ramps up in the morning and down in the afternoon. That behavior is the whole reason it suits solar: array output swings all day, and a pump that tolerates a swinging power input without stalling or short-cycling is worth more off-grid than raw flow figures on a spec sheet.
The tradeoff is that helical-rotor pumps are steady rather than fast. They are matched to fill storage over the course of a day, not to deliver a big instantaneous flow. That is the right shape for off-grid water, provided the system is designed around storage, which is the next piece.
Why the pump gets its own array
On the Torrance system, the pump runs from a dedicated 1,200 W array through an MPPT boost controller — not from the house solar system. There are two reasons we design it that way on most properties. The first is independence: a pump on its own array does not draw down the house battery on a run of cloudy days, so a heavy watering day never costs you the lights. The second is voltage. A boost controller lets a small array drive a pump whose operating voltage is higher than what the panels produce on their own, which keeps the array small and the wiring run manageable.
The generator auto-switch is the third leg. When solar production will not cover the demand, the controller transfers the pump to generator power without anyone walking out to the well head. On a property where the well is several hundred feet from the house, that convenience is the difference between a system people trust and a system people babysit.
Cisterns do the work batteries would otherwise do
Storing water is cheaper than storing the electricity it would take to pump that water after dark. That is the single most useful design rule in off-grid water, and it is why the Torrance job carries two 2,500-gallon NSF-61 cisterns rather than a bigger battery bank. NSF-61 is the certification that matters for anything touching potable water — tanks, pipe, and fittings alike — and we specify it throughout rather than mixing rated and unrated components in the same line.
Sizing the storage is a demand question, not a catalog question. Two numbers set it: how many gallons the household and any livestock use in a day, and what the well actually yields when it is tested. A modest well with generous storage often outperforms a stronger well with none, because storage decouples the rate you can pump from the rate you want to use. Cistern storage also lets you design the delivery side independently — gravity feed where the terrain gives you the elevation, a pressure pump and tank where it does not.
The line from the well to the house
The buried line is where New Mexico winters decide whether the design was any good. Ours on that job is 1.5 in. HDPE, NSF-61 rated, trenched to a minimum of 30 inches. HDPE is fusible, flexible enough to follow a rocky trench without a fitting every few feet, and forgiving if a line ever does freeze. Depth is the freeze protection, and on high-desert parcels it is not the line item to economize on.
What to have ready before you ask for a quote
- Well depth, static water level, casing size, and tested yield — or a note that the well is not drilled yet.
- Daily water demand: household occupants, livestock, and any irrigation.
- Distance and elevation change from the well head to the house or tank site.
- What the ground is like along that run — rock, caliche, or dirt changes the trenching line item.
- Whether a generator is on site or needs to be part of the scope.
The full write-up of the system described here, including the payment structure and what we would do differently, is on the Torrance County water system case study. If you are pricing the pump side on an existing well, start on the solar well pumps service page; if the well still has to go in, the well drilling page covers how we manage that with a licensed New Mexico driller.