Water Conservation Retrofit Calculator

Water retrofits save. This calculator payback.

Current water bill annual

Conservation % achievable

Retrofit capex

Unit count

Payback years

6.86

Annual savings

$25,500

Capex per unit

$972

How the math works

Annual savings = current bill × conservation %. Payback = capex / savings.

$85k bill × 30% = $25.5k/year savings. $175k capex / $25.5k = 6.9 years. Add rising rate trend: effective payback 5-6 years. Sub-10-year water retrofit typically pencils in drought markets.

How to Use

Enter current water bill annual.
Enter conservation % achievable.
Enter retrofit capex.
Enter unit count.
Read payback and unit economics.

Frequently Asked Questions

Typical savings?

Low-flow toilets (1.28 gpf vs 3.5 gpf): 30-40% unit water use. Low-flow showerheads: 15-25%. Smart irrigation: 20-40% landscape water. Combined: 20-40% total property water use. Cost varies by scope.

Unit costs?

Toilet replacement: $250-500. Showerhead swap: $20-50. Faucet aerators: $5-15. Smart irrigation controller: $200-800. Whole-unit retrofit: $600-1200. Portfolio-wide: scale discounts possible.

Water bill trend?

Water rates rising 5-8% annually (inflation + infrastructure + scarcity). Locked-in savings compound over time. Real dollar payback faster than nominal calculation. Future-proof against rate spikes.

How often should I rerun this?

Rerun this calculator whenever inputs change materially — new rent roll data, rate moves, loan balance updates, or quarterly operating data. For active deals, monthly refresh is typical. For stabilized assets under monitoring, quarterly is fine. Treat the output as a decision tool, not a one-time answer — market conditions evolve and so should your analysis.