Grundfos 5SQ05-90 (SQ 5-90, 230V, P/N 96160130)

What these numbers mean for an off-grid build

The table above is what the manufacturer publishes. This section is what those figures imply once the unit is doing real work, worked from this row and from the 17 products in the same table. The arithmetic is shown so you can check it against your own design rather than take it on trust.

Flow, and what it means in a day

Maximum flow is 7.5 gallons a minute, which is about 450 gallons an hour if it ran continuously at that rate, so filling a 500 gallon cistern takes roughly 1.1 hours of pumping. Maximum flow is measured at low head, and real output falls as the pump works against height and friction.

For most off-grid installations, slow and steady into storage beats fast and on demand. It lets a low-yield well recover, it keeps the surge off the inverter, and it moves the pumping into daylight hours when the array is producing. Lesson three covers why water gets designed before power, and the water usage calculator turns a household into a daily gallon figure.

Head, and where the pump can sit

Maximum head is 155 feet, meaning the vertical lift plus friction losses the pump can overcome before flow stops. Friction in the pipe run counts against that budget, so a pump lifting from a deep static level through a long horizontal run has less margin than the raw number suggests.

What it costs to run

Maximum draw is 5.2 A at 200-240 V AC, roughly 1,041,248 W at full load. Moving 100 gallons at maximum flow therefore takes on the order of 231.388 kWh, which is a useful way to see how pumping compares with the rest of the load list.

Startup draw is higher than the running figure on any motor, so both the inverter surge rating and the conductor size have to allow for it. Size the cable on the actual current and run length rather than by habit: the wire gauge calculator does the voltage-drop arithmetic, and on a long run to a well head the drop usually decides the gauge rather than the ampacity.

Where this type fits

Listed as AC submersible. Submersible pumps sit in the water and push, which works at depth and is the usual answer for a drilled well. Jet pumps sit at the surface and pull, which is easier to service and limited in lift. Diaphragm pumps are the common choice for pressurizing a cabin from a tank. Solar direct pumps run straight from panels with no battery, pumping whenever the sun shines into storage that provides the buffer, which is a resilient arrangement and slow by design.

Whichever type you choose, keep a spare of whatever is hardest to obtain and record the model and fittings in your systems binder. A pump failure in winter is a bad time to be learning the procedure. The spares reference lists what to hold for each system.

The closest alternatives in this table

Sorted by the specification that defines the category, these are the units in the water pumps table sitting nearest to Grundfos 5SQ05-90 (SQ 5-90, 230V, P/N 96160130) at 7.5 GPM. Comparing against near neighbors is more informative than comparing against the whole table, because it isolates the differences that are not simply size.

• SEAFLO 55-Series SFDP1-055-060-55 · 5.5 GPM
• RPS Solar Pumps RPS 200 Solar Well Pump Kit · 5.1 GPM
• Everbilt EFSUB5-122HD · 10.0 GPM
• Grundfos SQFlex 11 SQF-2 · 11.0 GPM

The full table sorts on every column, which is the fastest way to see whether a difference in price is buying a difference in specification or only a difference in brand.

How this fits with the rest of the system

A pump is chosen against the well or tank on one side and the electrical system on the other. Lift and flow have to suit the source; startup current and running draw have to suit the inverter and the cable. The inverter table lists surge ratings, which is the figure a motor start tests.

Where the source is a low-yield well, the right answer is usually a slower pump filling storage over hours rather than a powerful one meeting demand directly, which changes both the pump choice and the plumbing. The well pump calculator works the lift and flow, and lesson three covers the storage and freeze protection that go with it.

Checking these figures against the datasheet yourself

Check whether maximum flow and maximum head are quoted at the same operating point, because they are usually not: flow falls as head rises, and the useful figure is the curve rather than either endpoint. Confirm whether the amperage quoted is running or locked-rotor, and note the duty cycle, since some diaphragm pumps are not rated for continuous operation.

Two conventions catch people out across every category. The first is that a specification quoted without its test conditions is not really a specification, so where a datasheet gives a number and no conditions, treat it as marketing until you find the conditions. The second is that model names persist across silent revisions, so a sheet downloaded three years ago may not describe the unit in the box. The price index and the observed prices above are dated for the same reason.

Installing it, and living with it afterwards

Submersible installation means the pump lives at depth, so everything about servicing it involves pulling the drop pipe. Use a safety rope, torque-arrestors where the manufacturer calls for them, and a pitless adapter or well seal appropriate to your frost depth. Splices on the drop cable must be properly made and heat-shrunk; a failing splice is the most common reason a healthy pump stops.

Whatever the type, fit a pressure switch and a suitably sized pressure tank so the pump is not short-cycling itself to death, protect against dry running, and put a union either side of the pump so it can come out without cutting pipe. Record the model, the fittings, the wire size, and the setting depth in your systems binder, and keep the spares that are specific to it on the shelf. In winter, a pump failure is not the moment to be working out which parts you need.

Warranty, and what it is worth

The published warranty is 2 years. Off grid, the length of a warranty matters less than the mechanics of claiming on it: who pays freight on something heavy, whether a replacement ships before the failed unit is returned, whether the seller or the manufacturer handles the claim, and whether an owner installation voids anything.

Ask those questions before you buy rather than after a failure, and keep the purchase paperwork, serial numbers, and installation photographs with the systems binder. Where the unit is a single point of failure for something critical, the honest planning assumption is that a warranty replacement takes weeks, which is the argument for a spare or a second path rather than for a longer warranty. Lesson ten covers deciding which of those is worth paying for.

What separates one pump from another

Pumps are chosen by the shape of the job rather than by a single rating, and the specification that decides everything is the curve of flow against head rather than either figure alone.

Start with the source. A drilled well at depth calls for a submersible; a shallow source or a tank suits a surface or jet pump; a cabin pressurized from storage usually wants a diaphragm pump with a pressure switch and tank. A solar direct pump running straight from panels into storage removes the battery from the water system entirely, which is a genuinely resilient arrangement in a place where the pump is the critical component.

Then look at duty. Some pumps are rated for continuous operation and some are not, and a diaphragm pump asked to run all day will not last. Consider whether dry-run protection is built in, since running dry destroys most pumps quickly and a low-yield well makes that a real scenario rather than a theoretical one.

Finally, weigh serviceability against efficiency. The most efficient pump on the table is a poor choice if its parts are proprietary and slow to obtain, because a water outage is the one failure you cannot wait out comfortably. A slightly thirstier pump with common seals, a local supplier, and a spare on the shelf is usually the better off-grid decision.

Storage, pressure, and why the tank matters more than the pump

A pump is only half of a water system. What decides whether the taps behave is the storage and the pressure arrangement behind it, and most off-grid frustration with water traces back to those rather than to the pump itself.

Storage buffers a slow source. A well that recovers at a modest rate can serve a household comfortably if a cistern fills gently over hours and the house draws from the cistern, and it will disappoint badly if the house draws from the well directly. That single design decision often matters more than any specification on this page.

Pressure comes either from elevation or from a pump and a pressure tank. Gravity gives roughly one pound per square inch for every 2.31 feet of height, so a tank on a rise can run a house with no pump at all, which is the most reliable arrangement available. Where a pump is needed, a correctly sized pressure tank is what stops it short-cycling itself to death, and undersized tanks are the most common installation error in owner-built systems.

Keep one path to water that needs no electricity: a gravity feed, stored water, or a hand pump. That principle is covered in lesson ten, and the water usage calculator turns a household into the daily figure the storage has to cover.

Freezing, and the failures that follow

Water expands as it freezes and splits whatever contains it, which makes cold the most destructive thing that happens to a water system. The casualty is rarely the tank, which freezes slowly because of its volume. It is the pipe stub, the pressure switch, the filter housing, or the pump body, all of which can freeze in an hour.

Everything holding water must be below the local frost depth, inside heated space, drainable, or heat traced. Heat trace needs power, so the case to design for is a freeze and an outage at the same time. Bury lines to the depth your county actually uses rather than the depth quoted from somewhere else, slope them so they can be drained, and put the valves where you can reach them in a storm rather than behind the woodpile.

Surface and jet pumps are the most exposed and want an insulated, gently heated pump house with a heat source you can run from the battery bank. Submersibles are protected by depth, but the pitless adapter, the wellhead, and the run into the building are not. Lesson three covers the whole water design in order.

What the table cannot tell you

Every figure above comes from a published datasheet, and datasheets describe a unit under test conditions rather than in your building. They do not tell you how a manufacturer behaves when something fails inside the warranty period, whether spare parts will still be available in ten years, how the firmware behaves in an edge case, or whether the support line is answered by someone who knows the product. Those things decide as much of the ownership experience as the specifications do, and the place to learn them is from people running the equipment: the forum is a reasonable place to ask.

Nor does a datasheet describe the installation. Most off-grid equipment that disappoints its owner was undersized for the real load, wired with conductors chosen by eye, protected by fusing selected on price, or sited somewhere too hot, too cold, or too awkward to service. The equipment rarely fails on its own terms. Lesson six is the one to read before buying anything on this page, and the system planner puts the whole design together so the components are chosen against each other rather than one at a time.

Specifications here are recorded from the manufacturer datasheet or a primary retailer page on the date shown, with a confidence flag on every row. Manufacturers revise datasheets, and models are superseded without changing name. Check the current sheet before you spend money, and if you find a figure here that no longer matches the source, the corrections page is how to tell us; corrections are logged publicly rather than quietly edited. How this site researches sets out the rest.