Solar water pump designer · Free · No upload
Design a solar water pump system, then watch it work.
Drag a borehole or pond, a pump, solar panels, a pipe, a tank and your outlets onto a live scene, or start from a ready-made kit. Run the day and watch the sun move, the pump start, water fill the tank and the drip lines run. Take the sun away, thin the pipe or swap the pump and see what fails. A score lists what is right and wrong, with one-click fixes. Everything runs in your browser.
- Wells & surface water
- Pump · panels · pipe · tank
- Score & one-click fixes
- Metric & US units
What fkWater can do
Drag in real parts
Boreholes, ponds and rivers, four pump types, panels from 100 to 550 W, pipe sizes, tanks on a stand and drip, sprinkler, trough and household outlets. Tap any part to change it.
A live day, hour by hour
The sun crosses the sky, the pump starts only when the panels give enough power, water flows through the pipe and fills the tank, and the outlets draw it down. Speed up time, add clouds or switch the sun off.
Total head worked out properly
Lift, drawdown, pipe friction (Hazen–Williams), fittings and outlet pressure are added up, and a borehole’s yield stops the pump from running it dry.
A score and one-click fixes
A score out of 100 in four groups (water delivered, pipes and pressure, parts that fit, cloudy days). Each problem names the points it costs and offers a fix, such as a larger pipe, a taller tank or a submersible pump.
Kits in three sizes
Start from a garden drip system, a borehole to a drip field, livestock water, direct sprinklers or a village tank, in small, medium or large.
Pipe size or more panels?
The same job through every pipe size, with the array each needs and the water speed. A bigger pipe often costs less than the panels it saves.
Tank instead of batteries
Direct solar pumping stores water, not electricity. Size the tank for the days you need and test a run of cloudy days.
Share and take to a supplier
Auto-size the pump and panels, copy a short specification, or share a link that holds your whole design.
Private by design
The designer runs in your browser. Your projects are saved in this browser only and never sent to a server.
How to use fkWater in 5 steps
Start from a kit or an empty scene
Press “Start designing”, then open Kits and pick a system and a size, or drag parts in from the left.
Describe your site
Tap the source to set the water level and drawdown, the pipe for its length and size, and the outlets for how much water they use and when.
Run the day
Watch the pump start in the morning sun, the tank fill and the outlets draw it down. Speed up time, add clouds or take the sun away.
Read the score
Open Checks to see what costs points. Apply a one-click fix, or let Auto-size pick the pump and panels.
Share it
Open Size to compare pipe sizes and copy a specification for a supplier, or share a link to your design.
What people use it for
Irrigating a plot from a borehole
Find how many panels and what pump a drip system needs for a given well depth and area.
Watering livestock
Size a small pump and tank for cattle, goats, pigs or poultry in a place with no grid power.
Comparing quotes
Check that a supplier’s pump and panel quote fits your head, flow and sunshine before you pay.
Your files stay on your device
fkWater runs entirely in your browser. Your project is saved in this browser only, so you can come back later, and is never sent to our servers. A shared link carries your design in the link itself.
These pages use anonymous analytics (Google Analytics) for page views and feature use; file names and contents are never part of that data. Read more about privacy.
Browser support
Good to know
- fkWater is a planning estimate, not an engineering design. Real pump curves, drive limits, cable losses and pump efficiency vary by brand and by how hard the pump is driven.
- It models direct solar pumping (panels, drive, pump, tank), with no batteries and no grid or generator backup. Water storage is in a tank. One pipe runs from the pump to the tank or the outlets, with no branching network.
- Peak-sun-hours are an input. Look your site up (for example PVGIS or the Global Solar Atlas) and use the worst month you still need to irrigate in.
- Typical figures for crop water use, livestock drinking water, irrigation efficiency and pump efficiency are starting points. Change them to match your crop, animals and equipment.
- Very large systems (above about 40 kW of pump power) are outside what this tool is built for.
- fkWater is an early release, and features may be added or changed.
Frequently asked questions
Is fkWater free?
Yes. It is free, with no sign-up and no login.
How do I try different pumps, pipes or tanks?
Tap any part on the scene to change its size or type, or drag a new one in from the left. The simulation restarts with your change and the score updates straight away. Ctrl+Z undoes any change.
How big a solar panel array do I need for a water pump?
It depends on the water you need, the total head the pump must lift against and the sunshine at your site. Enter those and fkWater gives the array in watts and the number of panels, with a margin on a normal sunny day.
What is total dynamic head?
It is the full height the pump works against: the lift from the water to the outlet, the drawdown while pumping, the friction in the pipe and fittings, and the pressure needed at the outlet, all added together and measured in metres (or feet) of water.
Why does pipe size matter so much?
Friction rises steeply as water speeds up. A pipe that is too thin adds a lot of head, which makes the pump and the solar array bigger. The pipe table shows the array needed for each size so you can see where a bigger pipe saves money.
Do I need batteries for a solar water pump?
Usually not. Pump during the day and store the water in a tank. Water storage is far cheaper than batteries. fkWater sizes the tank for the number of days you choose.
Can a surface pump work from a deep well?
No. A surface pump pulls water up by suction, which is limited to about 6 m. For a well or borehole use a submersible pump. fkWater flags this mistake.
What are peak-sun-hours?
Peak-sun-hours are the hours per day at full strength sunshine that add up to the day’s total solar energy. Typical tropical sites are about 4.5 to 5.5, a cloudy season is about 3.5 and a dry sunny site is about 6. Use the worst month you must irrigate in.
What happens on a cloudy day?
A solar pump does not start below about 20% of its rated power, so output drops faster than the sunshine does. The chart compares a full-sun day with a half-sun day, and the tank carries you through.
How accurate is it?
It uses standard hydraulics (Hazen–Williams friction, hydraulic power) and typical efficiencies, so it is good for planning and comparing options. Always confirm the pump curve, drive input range and cables with your supplier.
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