💰 About This Category
What Are Cost & Comparison Calculators?
The Cost & Comparison category brings together eight free calculators designed for anyone who needs to make a financially informed decision about water storage. Whether you're a homeowner trying to cut utility bills, a rural landowner evaluating water supply alternatives, a property developer costing out a new build, or a facilities manager comparing tank replacement options — these tools give you real numbers to work with, not vague estimates.
Each calculator in this section goes beyond the sticker price. You'll find tools that calculate total cost of ownership over 10–20 years, compare material durability against upfront savings, and show you the exact year at which an investment pays for itself. The goal is to replace guesswork and sales brochures with transparent, objective calculations you can trust before committing to a purchase.
All tools are free, require no sign-up, and work on any device. Cost benchmarks are reviewed and updated quarterly to reflect current market pricing across major regions.
🧭 Guide
How to Choose the Right Cost Calculator
Start with the Water Tank Cost Calculator if you don't yet own a tank and need a ballpark figure for budgeting. It covers the widest range of tank types and sizes, and gives you a realistic price range before you approach suppliers. This is the right starting point for most homeowners and developers.
Use the Plastic vs Steel Calculator when you've narrowed it down to two material choices and want to see which is cheaper in the long run. Stainless steel costs more upfront but typically outlasts polyethylene by 10–15 years — this tool shows whether that longevity translates into real savings at your specific budget.
Run the Water Bill Savings Calculator if you already have a tank (or plan to install one) and want to quantify the financial benefit. It's especially powerful for households in areas with high water tariffs or those planning to harvest rainwater, where savings can be substantial over time.
Use the Delivery vs Tank and Borehole vs Mains calculators for rural or off-grid properties where the water supply itself is the main cost driver. These are decision-support tools: they model multiple years of costs side by side so you can see exactly when alternative supply methods outperform the status quo.
| Your Situation |
Best Calculator to Start With |
Key Output |
| Buying a first tank, unsure of budget |
Water Tank Cost |
Price range by size & material |
| Deciding between plastic and steel |
Plastic vs Steel |
Lifetime cost comparison |
| Wanting to reduce water bills |
Bill Savings |
Annual savings & payback period |
| Costing a full installation project |
Installation Estimator |
Total installed cost |
| Rural property on water deliveries |
Delivery vs Tank |
Break-even year |
| Considering drilling a borehole |
Borehole vs Mains |
Break-even year, 10-yr savings |
| Comparing multiple tank quotes per litre |
Cost Per Litre |
Cost efficiency metric |
| Choosing rooftop vs. underground |
Underground vs Rooftop |
20-year total cost |
Pro tip: Use the Cost Per Litre calculator as a quick benchmark when comparing quotes from multiple suppliers. A lower sticker price doesn't always mean better value — a larger tank at a modestly higher price often delivers significantly cheaper storage per litre.
❓ FAQ
Frequently Asked Questions
How much does a water tank cost on average?
A basic plastic water tank costs $100–$500 for small residential sizes (500–2,000 litres). Mid-range poly tanks from 2,000–10,000 litres run $400–$2,500. Stainless steel or fibreglass tanks at the same sizes cost 2–4× more. Installation adds $200–$2,000+ depending on location and complexity. Use the Water Tank Cost Calculator for a precise estimate based on your size and material choice.
Is plastic or steel cheaper for water storage?
Plastic (polyethylene) tanks are almost always cheaper upfront — often 40–70% less than stainless steel equivalents. However, steel tanks typically last 30+ years versus 15–25 years for quality poly, which can mean a lower total lifetime cost per litre stored, especially in high-UV climates. Use the Plastic vs Steel Calculator to see which wins for your specific budget and expected lifespan.
How much can I save on water bills with a storage tank?
Savings depend on your local water tariff, household consumption, and whether you're harvesting rainwater or using the tank to shift usage to off-peak tariffs. A typical household storing and using 5,000 litres per month could save $30–$120/month depending on local rates. Our Water Bill Savings Calculator generates personalised figures when you enter your current bill and usage data.
Is it cheaper to get water delivered or buy a tank?
For rural properties that regularly order tanker deliveries, buying a large storage tank almost always pays off within 1–4 years. Delivered water typically costs $0.10–$0.40 per litre, while mains-supplied stored water costs $0.001–$0.005 per litre. The Delivery vs Tank Calculator calculates your exact break-even year based on delivery frequency, distance, and tank investment.
What is the cheapest cost per litre for water storage?
Large polyethylene tanks in the 10,000–30,000 litre range typically offer the lowest installed cost per stored litre — often $0.10–$0.30/L. Smaller tanks cost more per litre ($0.50–$2.00/L) because fixed costs like base preparation and plumbing connections are spread over less capacity. Use the Cost Per Litre Calculator to compare any combination of tank sizes and prices.
Is a rooftop or underground tank more cost-effective?
Rooftop tanks are generally cheaper to install ($500–$3,000 all-in for a typical residential system) but add structural load and may require roof reinforcement. Underground tanks eliminate pumping costs if gravity-fed to rooftop fixtures, but excavation and backfill push installation costs to $3,000–$10,000+. Over 15–20 years, underground tanks often win on total operating cost if gravity pressure is sufficient. The Underground vs Rooftop Calculator models this comparison with your specific inputs.
How do I compare borehole vs mains water costs?
Borehole drilling costs $2,000–$15,000 upfront depending on depth and local geology, plus annual maintenance and water testing costs. Pump electricity typically adds $0.0005–$0.002 per litre. Mains water charges $0.001–$0.005/L in most regions. Boreholes generally pay back in 3–8 years if monthly usage exceeds 10,000 litres and mains rates are relatively high. Use the Borehole vs Mains Calculator to run the numbers for your location and usage profile.