Water Project Budget Allocator & Cost per Gallon
Split a well or septic budget across drilling, pump, trenching, treatment and contingency, and see the cost per gallon of capacity — with typical splits you can adjust.
Calculator
On a $12,000.00 budget, drilling gets $7,200.00 and the pump & tank $1,800.00 at your split, and the project works out to $12.00/gallon of storage capacity. These percentages are labeled typical planning splits — move them to fit your project.
Before you have firm quotes, it helps to see roughly where the money in a well or septic project goes. This tool splits a total budget across the usual buckets — drilling and casing, pump and pressure tank, trenching and wiring, treatment, and a catch-all for contingency — using typical planning shares you can override the moment you have real numbers. It also normalizes the total into a cost per gallon of capacity, a handy way to sanity-check one quote against another.
The default split is a labeled planning convention, not a rule. Drilling usually dominates a well budget, but geology, depth and your local labor market move every share — adjust them to fit your project and keep the five to a 100% total.
Formula
Each category is a share of the total, and the normalizer is a simple per-unit cost:
Category $ = total × category share
Cost per gallon = total ÷ capacity in gallons
The five shares are typical planning splits (drilling 60%, pump & tank 15%, trenching & wiring 10%, treatment 10%, other 5%) that you adjust; the calculator flags it if they do not add up to 100%.
Worked example
On a $12,000 budget with the default split, drilling gets 12,000 × 0.60 = $7,200, the pump and tank get $1,800, trenching and wiring $1,200, treatment $1,200 and other $600. Against a 1,000‑gallon capacity that is 12,000 ÷ 1,000 = $1.20 per gallon. Shift the shares to match your quotes — if your driller takes 70% of the total, drilling becomes $8,400 and the rest shrinks to keep the total at $12,000.
Using the split and cost per gallon
Use the split to spot an outlier. If a quote puts drilling at a far smaller share than usual, check whether casing, the pump or trenching were left out and quoted separately — the complete-system cost tool helps you rebuild the full line-item total. The cost-per-gallon figure is most useful for comparing storage: a bigger pressure tank or cistern spreads the fixed costs over more gallons, lowering the per-gallon number.
These are planning splits, not a bid. Every share is a labeled typical you can and should move, and the real budget comes from itemized written quotes for your site. Nothing here is a price list; the whole calculation is driven by the total you enter.
Reference table
Typical planning split of a whole rural-property water project (labeled typicals — adjust them to your own quotes).
| Category | Typical share |
|---|---|
| Drilling & casing | 60% |
| Pump & pressure tank | 15% |
| Trenching & wiring | 10% |
| Treatment | 10% |
| Other / contingency | 5% |