Introduction
Choosing the right size water tank is one of the most important decisions you’ll make when planning an efficient irrigation system. Whether you’re running a commercial nursery, managing crop production, or looking to future-proof your greenhouse, proper water storage is crucial.
In this guide, we’ll walk you through the key factors that affect tank sizing—and how to make the right decision for your space and setup.
Why Tank Sizing Matters
An undersized tank means you’ll constantly run out of water, compromising plant health and forcing frequent refills. Oversizing, on the other hand, can waste budget and space unnecessarily.
The right-sized tank should strike a balance between usage needs, refill rate, and available space.
Key Factors to Consider
A. Irrigation Volume Requirements
Start by calculating your daily or weekly water usage. This depends on:
Type of crops or plants
Area to be irrigated (in square metres or hectares)
Irrigation method (drip, sprinkler, ebb & flow, etc.)
➡️ Example: A commercial nursery using overhead sprinklers for 2,000m² may need up to 10,000 litres/day during peak season.
B. Water Source Availability
Rainwater harvesting? Consider rainfall patterns and collection surface area.
Mains or borehole-fed tanks? Look at refill speeds and consistency.
C. Seasonal Demand
Many nurseries or farms have peak watering periods. Your tank should hold enough water to get through a dry spell or power outage without disruption.
D. Available Space for Tank Installation
Sectional steel tanks are great for larger setups, while smaller poly tanks may work better in restricted areas.
Sector-Specific Sizing Advice
Nurseries & Garden Centres
Typical sizes: 5,000–25,000 litres
Need: Consistent watering multiple times a day, especially during warmer months
Bonus: Many use rainwater harvesting to reduce costs
Greenhouses & Polytunnels
Typical sizes: 2,000–10,000 litres
Need: Efficient and gentle delivery systems (often drip or ebb & flow)
Tip: Raised tanks can improve gravity-fed systems
Farms & Agricultural Applications
Typical sizes: 25,000–100,000+ litres
Need: High capacity for crops, livestock, or drought protection
Often modular or expandable tanks are ideal
Still Unsure? Let Us Help.
At KG Irrigation, we’ve installed hundreds of water tanks across the UK – from small nurseries to large-scale farms. We offer both galvanised steel and poly tanks, tailored to your setup, budget, and usage.
We’ll help you size it, source it, and install it – no guesswork required.
➡️ Contact us today for a free consultation.
