Losing water and money to the desert heat? Evaporation drives everything in the desert
EPA's WaterSense program estimates that, depending on climate, an uncovered 500-square-foot pool could lose between 12,000 and 31,000 gallons of water a year to evaporation, and more if heated. It notes evaporation is a leading cause of water loss, especially in hot, dry climates, and that solid pool covers can cut evaporation by more than 90% and save 50 to 70% of heating costs in heated pools (EPA WaterSense, Jump Into Pool Water Efficiency).
Evaporation matters for chemistry. Pure water leaves; dissolved minerals stay. Each top-off adds more minerals from the tap, so calcium and total dissolved solids climb over time in any pool, saltwater or chlorine. That is why draining and refilling, or partial dilution, eventually becomes part of desert pool ownership; see our Gilbert draining and backwash guide. A cover is the most effective way to slow the cycle.
Calcium scale and the salt cell
A salt cell works by electrolysis, and the cell plates are where calcium scale tends to form, especially when water is warm and pH runs high. Scaled plates make less chlorine and wear faster. Practical steps: test calcium hardness, pH and total alkalinity regularly, keep the cell inspected and cleaned as the manufacturer directs, and budget for eventual cell replacement. Ask your water utility for its published hardness data instead of relying on a general figure, since source water varies.
Chlorine pools face scale too, on tile lines and heaters, and stabilized tablets add cyanuric acid that also builds up with evaporation. Neither system escapes desert water chemistry.
Sun, heat and chlorine demand
Gilbert summers are hard on chlorine of either kind. Sunlight breaks down unstabilized chlorine, and warm water speeds up both sanitizer use and algae growth, so a pool needs more chlorine per day in July than in January. A chlorine pool owner meets that demand by adding more product; a salt system owner meets it by running the generator at a higher output or for more hours, which ties chlorine production to pump runtime. Cyanuric acid stabilizer slows sunlight losses in both systems, but it does not evaporate, so it also builds up over a season of top-offs.
A weekly routine for either system
- Test free chlorine, pH and total alkalinity at least weekly in summer, and calcium hardness, stabilizer and (for salt pools) salinity at least monthly.
- Keep pH in the range your equipment and surface manufacturers specify, since high pH speeds up scaling.
- Brush tile lines and inspect the salt cell or chlorinator for scale.
- Track how much water you add. A sudden jump can mean a leak rather than evaporation.
- Cover the pool when it is not in use if your layout and barrier allow it.
Pumps: federal rules and the rebate premise
It is often assumed that SRP pays a rebate for a variable-speed pool pump. SRP's residential rebate FAQ says it offered a pool pump rebate in the past, "but it's no longer available" (SRP residential rebates). Check SRP's current list before buying, but do not count a pump rebate in your budget.
Federal efficiency rules now do much of what rebates used to encourage. Under 10 CFR 431.465, dedicated-purpose pool pumps manufactured starting July 19, 2021 must meet minimum weighted energy factor (WEF) ratings. Integral cartridge-filter and sand-filter pumps must ship with a timer, and pumps with freeze protection must ship with it disabled or with specified default settings (10 CFR 431.465). A salt system needs enough circulation to make chlorine, so pump runtime and the pump's efficiency matter more with salt.
What it costs to run
No town, state or federal agency publishes pool contractor prices for this work, so get written, itemized quotes.
Comparing 10-year running costs
Against that, a salt pool no longer buys liquid chlorine or tablets for routine sanitizing. Your own chlorine receipts are the right number for the other side of the comparison; multiply a typical year's sanitizer spend by 10. Results also depend on whether your pump was already running long hours before the conversion and on your electric rate, so use your own bills for both.
How to decide
- Choose salt if you value steady chlorine levels and fewer chemical purchases, and you will maintain the cell.
- Stay with chlorine if your electric costs are high, your pump runtime is already short, or you want the lowest equipment cost.
- Either way, use a cover, run an efficient pump on a schedule, and test for calcium and dissolved solids. See our saltwater conversion guide and energy costs guide.
| Item | Town fee | Source |
|---|---|---|
| Town swimming pool permit, permanent or in-ground pool or spa | $300 | Town of Gilbert fee schedule (rev. 9/15/2026) |
| Town swimming pool permit, portable above-ground pool or spa | $140 | Town of Gilbert fee schedule (rev. 9/15/2026) |
| Wall or fence permit, with a single-family permit / separate single-family permit | $120 / $180 | Town of Gilbert fee schedule (rev. 9/15/2026) |
| Individual residential electrical or plumbing permit | $150 each | Town of Gilbert fee schedule (rev. 9/15/2026) |
| Re-inspection fee | $150 | Town of Gilbert fee schedule (rev. 9/15/2026) |
| Demolition permit | $150 | Town of Gilbert fee schedule (rev. 9/15/2026) |
Sources: Town of Gilbert, Development Services Fee Schedules (revised 9/15/2026), Applied Miscellaneous Building Fees (Resolution 4563, effective July 1, 2025). No public agency publishes pool contractor prices, so none are shown.