Off-Grid Water Pumping: De-Mystifying Solar for You and Your Customer

Four tips and key takeaways to get you up to speed on solar water pumping.

By Neil Bacoski

A common small livestock application that scales for depth and flow easily. Here is a two-panel system pumping from below 300 feet. Photo courtesy Solar Power & Pump Co. LLC in Elk City, Oklahoma.

Commercial solar water applications date back to the late 1970s, but the groundwater industry still considers solar water pumping to be an emerging technology that has been witnessed by many and tested by few.

This is partly because the supporting technology required for off-grid pumping—solar panels—continues to evolve quickly enough that systems that may not have made the cut just five years ago can now function more cost effectively in just that short a span of time.

So how does a water well system professional avoid having to relearn solar 101 every five years while generating a healthy margin that provides customer value? The answer may just lie in the panels themselves.

Know the Past to Understand the Future

To know the future, let’s start with a bit of history.

Some can remember when a 40-watt photovoltaic panel (PV, otherwise known as solar panel) cost $3000, or $75 per watt. The 1980s weren’t that long ago! Solar water pumping from any depth was not assured and probably not cost effective.

Eventually, however, panel prices dropped as demand increased until the $3 per watt threshold was broken. Suddenly, a 190-watt panel was cost effective and could run a quarter (¼) horsepower motor. This spurred innovation from some of the biggest names in water pumping still today, ushering in an era of reliable off-grid well pumping down below 600 feet.

Solar pumping is not just limited to wells at depth. Here is an example of a highly efficient DC solar booster pump pressurizing a tank on a single solar panel for a medium-sized household application. Photo courtesy Home Systems Consultant in Hawaii.

Today’s commonly available 400-watt commercial panel will soon generate 600, then 700, then 800 watts—but stay about the same physical size and price. The cost of panels and racking have traditionally made up a significant amount of the system cost. By lowering the number of solar panels needed, business cases that once made no sense are now competing head-on with grid tie systems.

In the groundwater industry, more of the total sale is captured by the driller/installer instead of the utility or other trades. That alone should make many water well system professionals take notice of the evolving business upside offered by off-grid pumping.

Four Tips to Remember

Some reading this are well versed in off-grid pumping. You may learn some tips as we move along, but the approach we recommend here is for those who know they’ll get a request to quote an off-grid system this year but are not sure where to turn. We’ll do this by:

  1. Developing a simple baseline case applicable to your average depth to water
  2. Determining who is your expert in specifying a solar system
  3. Determining who will do the solar integration
  4. Practicing by quoting.

Taking what we’ve learned about panels thus far, think about general system sizing from the sky on down. The reasons for this are many. Most of the off-grid water pumping is for livestock and irrigation requiring between 4 and 6 gallons per minute (GPM) down to 900 feet. This doesn’t cover all systems by any means, but it is a very usable average for us to work with.

This single-panel system is set to flow 4 gallons per minute from 125 feet and uses a float switch to shut off the pump when the tank is full. Even in northern climates a system like this can pump upwards of 1700 gallons in a day at a reasonable cost to the end-user. Photo courtesy Solar Power & Pump.

Most commercially available solar pump manufacturers have products that can work with these requirements and only require one to four solar panels to get it done.

1. A simple baseline case to help you understand what you would face on an average application

For the most part, many drillers/installers have an average depth to water in their installation area. They know they’ll hit water within 20% of this depth most of the time because they just know. If we work from the sky on down, we can get:

About 4 GPM from

– 1 panel = 175 feet
– 2 panels = 650 feet
– 3 to 4 panels = 850 feet

Or 10 GPM from

– 1 panel = 50 feet
– 2 panels = 100 feet
– 3 to 4 panels = 425 feet.

These are general guidelines that can be used as a rule of thumb. The purpose, however, is to get you to decide: “For my average depth to water and flow, how many panels would I need for the system if asked?” Remember that answer.

2. Determine your expert

The most successful first installations are rewarded to those who do some preparation ahead of time.

Figuring out who you’ll call to help you spec out your one-, two-, or three-panel system is a key step in being ready.

Maybe your favorite pump distributor also has solar options, but is the person you’re talking to an expert? Maybe a solar-only distributor is what you’ll need. Whoever you start working with, ask what is this person’s primary responsibility? Do they spend most of their time working on solar applications, or other things? Do you want to be buying and installing your first solar with a distributor who is also buying and installing their first solar system? Possibly not.

More and more experts are developed each year, so don’t fret, but also figure out who will be your solar expert and ask them for a quote for your one-, two-, or three-panel system. You’ll begin to get a feel for both the mechanical and electrical components that go into integrating an off-grid solution, but also gain confidence that you can give your end-user a solid number when they start asking about using solar.

This step alone will take you 90% of the way towards your first installation if you can get it done ahead of time.

3. Determine who will do the solar integration

First, what do we mean by integration? Solar water pumping systems are comprised of many parts to make the whole. Mechanical systems are more intuitive (pole and racks) and in line with everyday practice (pipe, valves, etc.). Electrical systems should be straightforward but oftentimes are over-complicated by inexperience.

For instance:

– Panels can vary by physical size and electrical output.
– Panels can be wired several different ways.
– Controllers can be integrated into the pump or above ground.

A rule of thumb: Try to have a system designer spec the electrical parts from a single source. This cuts down on variability of panel-to-controller-to-pump wiring and integration, especially if multiple panels are used in the system. This is less of an issue for single panel systems, but it is important that you have the right expert and get a baseline system in mind, including costs.

4. Practice by quoting

Once you’ve started installing solar-based water pump systems, most of you will find that you will be quoting a very similar system repeatedly. Practice makes perfect, but it also lets you begin to integrate different parts yourself, which can improve margins.

Key Takeaways

  • Before you’re ever asked to quote, try to determine who will be your expert. This could be your distributor, a manufacturer, or even another driller or pump installer who has done this before.
  • It’s helpful if your expert can also source the entire electrical system in-house.
  • Work with your expert to quote out a baseline system for your average depth and flow.
  • Don’t get fancy. Quote a one-, two-, or three-panel system so you can understand the parts (or quote them all).
  • If your expert cannot source the entire electrical, find a source who will integrate all the electrical parts in the order.
  • Keep these quotes in your pocket. They’re a reference you will certainly use.
Learn More from Groundwater Week 2022 Workshop
Bacoski presented on solar water pumping at Groundwater Week 2022. Click here to learn more.

Neil Bacoski is general manager of Solar Power & Pump Co. LLC, the manufacturer and distributor of SunRotor and Dankoff Solar off-grid pumps. Solar Power & Pump started in 2001 in Elk City, Oklahoma, and distributes more than 1000 complete solar pumping systems each year to drillers/installers, giving them a wide knowledge base with which to share in the groundwater industry. Bacoski is available to speak at state and industry trade shows and can be reached at