Best Storage Tanks in the UK: Where to Buy, How to Choose, and What to Know

Why picking the right storage tank matters

Choosing the correct storage tank is more than picking the biggest container you can find. Whether you're collecting rainwater for your garden, storing diesel for a generator, or keeping oil for heating, the right tank affects safety, cost, and how often you'll need to fiddle under the lid. You want a solution that fits the space, lasts for years, and doesn't turn into a constant hassle.

What people typically use storage tanks for

Most homeowners and small businesses use tanks for rainwater harvesting to water gardens or flush toilets, for emergency water storage, or for fuel and oil storage. Gardeners might keep a 100 to 250 gallon tank by a shed, while farms and tradespeople often need 500 to 2,000 gallon tanks for fuel and water on site. I always suggest thinking about both daily needs and occasional spikes—are you watering a small lawn or supplying irrigation to 2–3 raised beds?

Types of storage tanks you'll find in the UK

Not all tanks are built the same. Material, shape, and certification change what a tank is best for. Here’s a quick tour of the most common types you’ll encounter when shopping in the UK.

Plastic (polyethylene) tanks

Rotationally moulded polyethylene tanks are lightweight, resistant to rust, and inexpensive. They’re great for rainwater and many liquid fertilizers. Sizes typically range from small 25–100 gallon butt tanks up to 1,000+ gallon water storage. They’re easy to move, easy to install above ground, and often UV-stabilised so they don't fall apart after a single summer.

Steel and bunded tanks

Steel tanks, often used for diesel or heating oil, are tougher for heavy-duty or commercial use. Older single-skin steel tanks can corrode if not maintained, so many buyers now opt for bunded tanks—these have a secondary containment layer to capture leaks. Bunded tanks come in capacities from a few hundred to several thousand gallons and are a must where regulations require spill protection.

Fiberglass and modular tanks

Fibreglass tanks are corrosion-resistant and lighter than steel for their strength, making them a solid mid-range choice for both liquids and fuels. Modular tanks—interlocking plastic or metal tanks—are useful when space is constrained and you need a flexible footprint; stack them or arrange them to fit odd corners.

Top UK retailers and specialist suppliers

When you're ready to buy, you’ll want a retailer that stocks the type and size you need, has sensible prices, and offers reliable advice. Below are well-known stores and specialist suppliers in the UK that commonly stock storage tanks.

B&Q

B&Q is a go-to for homeowners looking for garden water butts and smaller polyethylene tanks. Their range covers small water butts in the 25–75 gallon range up to larger 200–300 gallon barrels suitable for garden irrigation. They often have easy-to-install accessories like tap kits and stands.

Wickes

Wickes offers a mix of garden and trade-focused tanks, including slimline tanks that fit against walls and larger free-standing options. If you're after a water butt that blends into the backyard or a tank that fits a narrow alleyway, Wickes is a good place to check.

Screwfix

Screwfix is popular with tradespeople for fuel and water tanks. They carry well-known brands and items like bunded diesel tanks and larger poly tanks in the 200–1,000 gallon range. Screwfix’s trade-focused stocking and click-and-collect convenience make it easy to get a job-site-ready tank fast.

Homebase

Homebase is similar to B&Q for garden use, with a solid range of decorative water butts, slimline tanks, and basic pumps and fittings. If you want something that won’t be an eyesore behind a patio chair, Homebase often carries aesthetic options and accessories to tidy installation.

Travis Perkins and Jewson

Travis Perkins and Jewson focus on trade and construction customers, stocking larger-capacity tanks—especially bunded fuel storage and construction site water tanks. If you're running a building project or need a heavy-duty solution, these outlets supply professional-grade equipment and advice.

Amazon UK and eBay

Online marketplaces like Amazon UK and eBay offer breadth: garden butts, slimline tanks, bespoke-sized containers, and imports you might not see on the high street. The trick here is vetting sellers and brands—reviews help, but make sure the tank suits UK regulations (especially for fuel or oil).

Specialist suppliers and The Tank Shop

For larger or specialist needs, look to firms dedicated to tanks—The Tank Shop, Plumbase, and independent suppliers that specialise in water harvesting or commercial fuel storage. These suppliers usually offer delivery with lifting and can advise on bunding, fittings, and compliant installation.

How to choose the right size and capacity

Picking capacity is less mysterious than it looks. Start by listing what you’ll store and how often it needs refilling, then match demand to tank size. Remember: space and access matter as much as gallons.

Calculating how many gallons you need

Estimate daily usage and multiply by the number of days you want stored. For rainwater used only for watering, a week of supply for a medium garden might be 100–200 gallons. Households keeping water for emergencies often choose 500–1,000 gallons to maintain toilet flushing and minimal washing. Tradespeople keeping fuel on site will calculate equipment burn rates—say a 20 gallon per day usage suggests a 200–500 gallon tank to reduce refuelling frequency.

Space and footprint considerations

Tanks can be bulky. A 500 gallon above-ground poly tank might be roughly the size of a small garden shed corner, while a 1,000 gallon unit could measure several feet across. Think about access for delivery (can a 10–12 foot delivery vehicle reach your driveway?), placement—near where the water or fuel will be used—and local regulations if you plan to permanently install a large tank in view of neighbours.

Installation and placement tips

Install badly and you’ll spend weeks regretting the leak or the trip hazard. Do this part right and your tank will hum along quietly for years.

Ground preparation

Above-ground tanks need a flat, level base. A compacted gravel pad or a concrete slab is standard for anything over 100 gallons. For smaller garden butts, a sturdy wooden stand or paving slab often suffices. If a tank sits unevenly, stress points can crack the shell or wear fittings prematurely.

Above-ground versus buried tanks

Buried tanks save space and keep water cooler, but they are more expensive to install and harder to inspect. Above-ground tanks are easier to access, install, and maintain. For fuel, buried tanks have extra regulations and risk; many homeowners and tradespeople prefer bunded above-ground tanks for easier monitoring and spill containment.

Materials, durability and maintenance

The material you choose defines maintenance and lifespan. Think of material choice as an insurance policy: more durable materials cost more up front but often save effort and money down the line.

Lifespan expectations

Poly tanks, if UV-stabilised, can last 15–25 years above ground. Steel tanks can go longer if properly maintained but will rust without care, especially near salty coastal air. Fibreglass tanks resist corrosion and can last decades with minimal upkeep. Bunded tanks protect against leaks and are required for many fuel applications, adding peace of mind and often meeting legal requirements.

Routine maintenance

Keep outlets clear, clean sediment from the base if storing water, and inspect seals and taps regularly. For rainwater harvesting, a simple first-flush diverter prevents roof grime from entering the tank. For fuel, monitor water in the bottom and use filters to prevent contamination. A quick check every few months can stop little problems turning into expensive repairs.

Cost factors and how to compare prices

Price is more than the sticker. Think delivery, installation, fittings, and long-term maintenance. A cheap tank now might triple your costs in repairs later if it’s the wrong type.

What affects the price

Material, capacity, brand, certifications (like for fuel or potable water), and whether the tank is bunded all affect cost. Accessories—stands, taps, pumps, and filters—add up, so budget for them. Delivery can be significant for large tanks; some suppliers include delivery with a crane drop-off, which is handy when you can’t handle heavy lifting.

Getting the best deal

Compare like-for-like: a 500 gallon bunded diesel tank from one supplier should be compared to another 500 gallon bunded unit, not to an unbunded poly water tank. Look for warranties, local dealer support, and whether the supplier offers fitting services. Seasonal sales and trade accounts at places like Screwfix or Travis Perkins can reduce costs if you’re buying multiple items.

Sustainability and rainwater harvesting

Using a storage tank for rainwater has practical and environmental benefits. It reduces mains water usage, lowers bills, and keeps your garden resilient during dry spells. If sustainability matters to you (and it probably does), a tank is one of the easiest low-tech switches that pays for itself.

Benefits of collecting rainwater

Collected rainwater is excellent for watering plants because it’s free of chlorine and usually softer than mains water. For outdoor cleaning, washing tools, or topping up ponds, it’s ideal. Over a season, a well-sized tank can cut municipal water use noticeably, especially on larger plots.

Basic filtration and safe use

For garden and outdoor use, a simple mesh filter and first-flush diverter will keep most debris out. If you plan to use harvested water for anything potable, you’ll need proper filtration and certified plumbing—don’t assume harvested water is safe to drink without treatment. For flushing toilets or washing machines, check appliances’ warranties and recommended water quality first.

Quick buying checklist

Before you press “buy,” run down this short checklist: What liquid will you store? How many gallons do you need? Is the tank suitable for that liquid (potable vs non-potable vs fuel)? Will it fit and can it be delivered and installed? Does it meet any legal or safety requirements for your use? If you tick all the boxes, you’re ready to order with confidence.

Conclusion

Buying a storage tank in the UK boils down to defining the purpose, matching capacity and material, picking the right retailer—be it a high-street DIY store, a trade supplier, or a specialist shop—and installing it properly. Think of the tank as an investment in convenience and resilience. A well-chosen tank will save you time, reduce costs, and keep things flowing smoothly for years. Want a tank that disappears into the background and just works? Plan carefully, pick the right material, and don’t skimp on installation.