Enter your drilling costs, pump specs, and current water bill to instantly see which supply option saves you more — and exactly when you'll break even.
Fill in your numbers — pick your currency below; every money field uses it
🔩 Borehole — One-Time Capital Costs
Drilling Cost
$
Pump & Equipment
$
Filtration / Treatment
$
Pipework & Connection
$
⚡ Borehole — Annual Running Costs
Annual Electricity
$/yr
Annual Maintenance
$/yr
Annual Water Testing
$/yr
🚰 Mains Water — Annual Costs
Daily Water Usage
Water Tariff
Annual Standing Charge
$/yr
Annual Water Rate Rise
%/yr
Enter the volumetric rate for water supply only. If your sewer or wastewater charge is also based on metered water, it may not fall when you switch to a borehole — check with your utility before adding it.
⚙️ Options & Estimates optional
Currency
Keep Mains as Backup?
Replace Pump Every
Total Pumping Lift
m
Electricity Price
$/kWh
Don't know your pumping electricity? Leave "Annual Electricity" blank and enter the total lift — the depth to the water level while pumping, plus about 30 m for a typical 3-bar pressure tank — and your power price. The estimate assumes the pump turns 40% of the electricity it uses into lifting work.
⚠ Please enter all required values: drilling cost, pump cost, daily water usage, and water tariff.
WaterTankCalculator.com — Borehole vs Mains Water Cost Comparison
Your Comparison Results
Verdict
—
—
Break-Even Point
—
years to recover borehole investment
Borehole Capital
— total
Borehole Annual Cost
— /yr
Mains Annual Cost
— /yr
Annual Saving (yr 1)
—
10-Year Total Saving
—
20-Year Total Saving
—
Cumulative Cost Over 20 Years
Borehole
Mains
📖 How To Use
How to Use This Borehole vs Mains Water Cost Calculator
This borehole cost comparison tool takes under two minutes to complete. Here's what to enter:
Enter your borehole capital costs
Include drilling (with casing and the yield test), the pump and equipment (pump, pressure tank, controls, cabling), any filtration or treatment, and pipework to the house. Get quotes from a licensed or registered driller — costs depend mostly on depth and rock type. If you haven't tested the water yet, put a realistic treatment allowance in rather than zero.
Enter your annual borehole running costs
Enter annual electricity for the pump, servicing (including UV lamps or filter cartridges), and water testing. If you don't know the electricity, leave it blank and use the lift and power-price fields to estimate it. The US EPA advises private well owners to test every year for total coliform bacteria, nitrates, total dissolved solids and pH. In England, a supply serving a single home is only monitored by the council if the owner asks, so budget for testing yourself.
Enter your current mains water usage and tariff
Find your daily volume from your water bill (yearly volume ÷ 365) and enter the water-supply rate per kilolitre, per 1,000 US gallons, or per cubic metre. Add the annual standing or fixed charge. For the yearly rate rise, look at how your own utility's prices have changed — the calculator uses 3% if you leave it blank.
Set the options
Pick your currency, say whether you will keep the mains connection as a backup (you then keep paying its standing charge), and choose how often the pump is replaced — its cost is added again at that interval.
Click Compare Costs
The calculator shows your break-even year, year-1 saving, and net savings at 10 and 20 years, with a note explaining the running costs it used. The bar chart compares total 20-year spend for each option.
Tip: A well-built borehole can last for decades, but the pump usually doesn't — submersible pumps are commonly replaced every 10–15 years. The calculator adds your pump cost again at the interval you choose, so a long break-even isn't flattered by ignoring it.
📐 The Formula
How the Borehole vs Mains Water Cost Formula Works
The comparison adds up each option's costs year by year (a cumulative cash-flow comparison, without discounting) and finds the year the borehole has cost less in total. Here's the core logic:
Mains Annual Cost (Yr N) = Daily Usage × 365 × Tariff × (1 + Rate Rise)N−1 + Standing Charge Borehole Annual Cost = Electricity + Maintenance + Testing (+ Standing Charge if mains kept as backup) Pumping Energy (kWh/yr) = Volume (m³/yr) × Lift (m) ÷ (367 × 0.40) Borehole Total to Year N = Capital + Σ Annual Cost + Pump Cost at each replacement Break-Even Year = first point where Cumulative Mains Cost ≥ Borehole Total (interpolated within the year) Net Saving at Year N = Cumulative Mains Cost − Borehole Total
The volumetric part of the mains bill rises each year by the "Annual Water Rate Rise"; the standing charge is kept flat. Borehole running costs are kept flat too, which slightly favours the borehole if your electricity and servicing prices rise. The 367 in the energy formula is 3,600 ÷ 9.81 — it converts lifting one cubic metre of water one metre into watt-hours — and 0.40 is an assumed overall pump-and-motor efficiency for a small submersible. Lifting 1 m³ through 100 m therefore uses about 0.68 kWh.
Tariff Unit Conversions Used
Input Unit
Converted to
Multiplier Applied
per kilolitre (kL)
per litre
÷ 1,000
per 1,000 US gallons
per litre
÷ 3,785.41
per cubic metre (m³)
per litre
÷ 1,000 (1 m³ = 1 kL)
Typical Borehole Cost Ranges (2025–2026)
Region
Drilling (per metre)
Total Installed (typical)
Annual Running
UK
£80–£180/m
£5,000–£18,000
£300–£800
USA (rural)
$15–$50/ft
$5,000–$15,000
$400–$1,200
Australia
A$60–A$150/m
A$4,000–A$12,000
A$350–A$900
South Africa
R250–R600/m
R30,000–R80,000
R3,000–R8,000
Kenya / E. Africa
$30–$70/m
$3,000–$12,000
$200–$600
Rough planning ranges only, not quotes — they are not from a single survey and will date. Depth drives the price most: a borehole that has to go twice as deep costs roughly twice as much to drill, before the bigger pump it needs. Rock hardness, casing, local rules and site access do the rest. Always get at least three written quotes, and ask what yield test is included.
🏠 When to Consider a Borehole
When Does a Borehole Make Financial Sense?
🏡
Rural Properties
Where the nearest main is far away, the cost of extending it can exceed the cost of a borehole. In that case compare the borehole with the connection fee, not just with water bills.
🌾
Agricultural Use
Irrigation, livestock and greenhouses use far more water than a home, so the same borehole saves far more each year and pays back much sooner. Check the abstraction limits where you are.
🏗️
New Builds Off-Grid
When building in an area without mains infrastructure, a borehole is often the only viable option — the cost comparison is against the prohibitive mains connection fee.
💧
High Mains Water Rates
Higher tariffs shorten the payback, but volume matters as much as price. A home using 500 L a day buys about 183 m³ a year — at 3 per m³ that is about 550 a year, which takes a long time to repay a borehole costing several thousand.
🔒
Water Security
In regions with frequent supply disruptions or hosepipe bans, the value of uninterrupted access often justifies a borehole beyond pure cost calculations.
📉
Rising Mains Costs
Price rises compound. At 5% a year, 20 years of water bills add up to about 1.65 times what 20 years at today's price would cost; at 8% a year, about 2.3 times. Test a few rates in the calculator.
When Mains Water Is Likely Better
Mains water usually wins when the borehole would be deep or in hard rock, the yield test shows low flow, the water needs expensive ongoing treatment, your household uses little water, or mains water is cheap. Urban homes with a mains connection already in place rarely recover the cost of a borehole on bills alone — the case then rests on garden or irrigation use, or on water security.
🧮 Worked Example
Worked example: a home with a large garden
Illustrative figures, not a quote. The household uses 1,200 L a day including the garden. Water costs 5.00 per m³ plus a 120 standing charge a year, rising 3% a year. The borehole costs 9,000 to drill, 2,000 for the pump and equipment, 800 for treatment and 700 for pipework — 12,500 in total. Servicing is 150 a year and testing 150. Electricity is left blank and estimated from a 70 m total lift at 0.17 per kWh. The mains is disconnected and the pump is replaced every 12 years.
Water used: 1,200 L × 365 = 438 m³ a year. Mains in Year 1: 438 × 5.00 + 120 = 2,310.
Pumping energy: 438 × 70 ÷ (367 × 0.40) ≈ 209 kWh, about 36 a year — small next to servicing and testing.
Borehole running cost: 36 + 150 + 150 = 336 a year, so the Year-1 saving is 1,974.
Break-even: about 5.8 years. With the pump replaced in year 13, the net saving is about 10,451 after 10 years and 40,036 after 20.
Change the usage to 400 L a day — a smaller home without a garden — and the Year-1 saving falls to about 538, the break-even stretches to about 18.8 years, and the 20-year saving shrinks to roughly 1,300. For a borehole, how much water you use matters as much as what you pay for it.
❓ FAQ
Frequently Asked Questions
Is borehole water cheaper than mains water in the long run?
It can be, but not automatically. A borehole swaps a water bill for a large upfront cost plus electricity, servicing, testing and an occasional new pump. It pays back fastest when you use a lot of water (a big garden, irrigation, livestock), when mains water is expensive, or when connecting to the mains would be costly. A small household with a modest bill may wait 15–20 years or more. In the worked example on this page, a home using 1,200 L a day breaks even in under 6 years; at 400 L a day the same borehole takes about 19 years.
How much does it cost to drill a borehole for a house?
There is no single price: it is driven mainly by depth, rock type and your country's rates. As a rough planning range, many domestic boreholes in higher-cost countries come to somewhere around 5,000 to 18,000 in local currency once drilling, casing, the pump, pressure tank and connection are included — and deep or hard-rock holes cost more. Get several written quotes that state the depth, casing, yield test and pump size, and budget separately for a water test and any treatment it shows you need.
What are the annual running costs of a private borehole?
Electricity is often smaller than people expect: lifting 1 m³ of water through 100 m with a typical small submersible uses about 0.7 kWh, so a home pumping 180 m³ a year from that depth needs roughly 120 kWh. The bigger items are usually servicing (pump checks, UV lamps, filter cartridges), yearly water testing, and saving towards a replacement pump every 10–15 years. Leave the electricity field blank and enter your lift and power price to let the calculator estimate it.
How long does a borehole last?
A correctly drilled, cased and maintained borehole can last for decades, though yield can fall if the screen clogs or the water table drops. The submersible pump is the part most likely to need replacing, commonly every 10–15 years; this calculator adds its cost again at the interval you choose. Pressure tanks, controls and treatment parts also need replacing from time to time.
Is borehole water safe to drink?
Borehole water requires testing before use as drinking water. Common issues include high iron, manganese, hardness (calcium/magnesium), nitrates, and occasionally bacterial contamination. A laboratory test tells you what treatment, if any, is needed — often sediment filtration and UV disinfection for bacteria, with specific treatment for iron, manganese, hardness or nitrates. The US EPA advises testing private wells every year for total coliform bacteria, nitrates, total dissolved solids and pH, and again after floods or if the taste, smell or colour changes.
Do I need planning permission or a licence to drill a borehole?
Rules vary by country. In England, the Environment Agency says you are likely to need an abstraction licence to take more than 20 m³ (20,000 litres) a day, and you may need its consent before drilling a borehole to abstract groundwater; Wales, Scotland and Northern Ireland have their own regulators. In the USA, rules are set state by state, and many states require a licensed driller and a well permit. In Australia, each state has its own licensing framework. Check with your local authority or environmental agency before drilling.
What break-even period is acceptable for a borehole?
That depends on how long you will stay and how much you value a secure supply. As a rule of thumb, a break-even well inside the time you expect to own the property — and inside the pump's 10–15-year life if you have not included a replacement — is a reasonable financial case. After break-even the water is not free: you still pay for power, servicing and testing. If the break-even is longer than you expect to stay, the borehole only makes sense for reasons other than cost.
Can I use mains water as backup alongside my borehole?
Yes — many properties keep a mains connection as backup, especially where the aquifer drops in dry seasons. You then keep paying the standing charge, so choose "Yes" under "Keep Mains as Backup?" and the calculator adds it to the borehole side. The volumetric saving still applies as long as the borehole is your main source. The two supplies must be kept physically separate, with approved backflow protection, so borehole water can never enter the public main.
✅ Sources & Review
Sources and review
The cost figures in this calculator are yours; this page explains the method and points you to the rules and guidance that matter before you drill:
US EPA — Protect Your Home's Water: test private wells every year for total coliform bacteria, nitrates, total dissolved solids and pH.
Reviewed by John Mac, PE, Water Systems Specialist
Texas-licensed Professional Engineer with 13+ years in residential water storage and 180+ tank projects. John writes and reviews every calculator on this site.
