Solar for Pools and Water: Covers, Pumps and Fountains

Solar gear for water does one of two jobs: it holds the sun’s heat in a pool, or it uses a small solar panel to move water with no outlet nearby. This section covers solar pool covers, solar water pumps for wells, gardens and stock tanks, and solar fountains for bird baths.

Solar pool covers

A solar pool cover floats on the water, bubble side down, and keeps heat and water in the pool. The EPA’s WaterSense program says a cover can prevent up to 95 percent of pool water evaporation, and that a cover used consistently helps the water hold its heat, with less cleaning and lower chemical use as well. WaterSense notes that covers come in manual, semi-automatic and automatic versions; a solar blanket is the manual, low-cost end of that range.

Covers are sold by pool size and shape, and an odd size takes the next size up, trimmed to fit. Our guide to solar pool covers has a sizing table for round, oval, rectangular and freeform pools, and explains how clear and blue covers differ.

Solar water pumps for wells, gardens and stock tanks

A solar water pump runs straight from its panels and pumps whenever the sun is up. The National Center for Appropriate Technology (NCAT), a nonprofit that advises farmers and ranchers, says solar pumping suits jobs with modest lift and modest volume: filling a stock tank, drawing from a shallow well or feeding small drip irrigation. Deep wells and large volumes call for specialized pumps and bigger panel arrays, and most pressurized sprinkler systems need far more power than solar can supply economically.

Two choices shape the rest of the setup:

• Submersible or surface. A submersible pump sits below the water in a well and needs no priming. A surface pump sits at or near the water and pushes it along a pipeline.
• Tank or battery. NCAT generally recommends storing three to 10 days of water in a tank instead of storing power in batteries, which add cost and upkeep.

NCAT puts most water pumping systems at two to six panels, with the exact number set by how much water you need and how high it has to rise. For livestock, size for the hottest week of the year: NDSU Extension says animals’ water needs vary with species, size and diet, and rise with temperature. Our guide to solar water pumps compares pump types, gives sizing examples from working ranches and covers float switches and freeze protection.

Solar bird bath fountains

Solar fountains are the small end of solar water gear: a palm-sized pump, a fountain head and a little panel, either floating on the water or on a cord. The Oklahoma Department of Wildlife Conservation recommends moving water to attract the widest range of birds, and suggests a bath only 1 to 2 inches deep with a rough bottom and a dry edge.

The main choice is power. A direct-drive fountain sprays only in direct sun. A battery backup model stores some of the day’s charge to keep running when clouds pass; Smart Solar, a fountain maker, sells both kinds and labels its compact birdbath model as direct sun only.

A fountain does not replace fresh water. The CDC lists bird baths among the things to empty and scrub once a week to keep mosquitoes from breeding, and the State of Illinois’s Keep Cool Illinois guidance says to change the water every 3 to 4 days. Our guide to solar bird bath fountains covers placement, sizing the fountain to the bowl and winter storage.

How to choose solar gear for water

Start with the job, then with where the sun falls.

Gear with a panel works only as well as the sun on that panel. Place the panel in open sky, away from the shade of trees, fences and the house, and remember that winter shadows are longer than summer ones. A dusty or leaf-covered panel charges more slowly, so a quick rinse helps; see how to clean solar panels.

Bigger solar setups around the yard

A pool cover needs no power at all, and a fountain pump runs from its own small panel. Larger jobs, such as running tools in a shed, need a separate panel and battery. Our guide to small solar panels covers what a 10 to 100 watt panel can charge, and grid-tied vs off-grid solar explains when a stand-alone system makes sense. To move air rather than water, such as venting a greenhouse, shed or chicken coop with no outlet nearby, see our guide to solar powered fans.

Related solar guides

Small solar panelsWhat a 10 to 100 watt panel can charge, with simple sizing math.

Outdoor solarSolar lights and gear that charge themselves outside.

Off-grid or grid-tiedWhen a stand-alone solar system makes sense.