If you own a pressure washer but have no access to a tap or garden hose nearby, a water tank for pressure washer setups is the solution you’ve been looking for. Whether you’re cleaning a farm, a driveway far from your house, or a remote construction site, a dedicated water storage tank keeps your machine running at full power — without interruption.
In this guide, we’ll cover everything: tank sizes, materials, how to connect them, top product picks, and expert tips to maximize your pressure washing performance.
Quick Answer: A water tank for a pressure washer is an auxiliary water storage container — typically 100L to 1000L — that feeds water directly into your machine when a mains supply is unavailable. The right tank size depends on your washer’s GPM (gallons per minute) flow rate.
JH
James Harlow — Equipment Specialist
James has 12+ years of experience reviewing pressure washing equipment for commercial and residential use. His work has been featured in Cleaning Industry Journal and ProWash Magazine.
2.5×
More run time with right tank
60%
Users lack mains access on jobs
£80+
Avg cost of a quality 200L tank
10yr+
Lifespan of poly water tanks
What Is a Pressure Washer Water Tank?
A pressure washer water tank — also called a water bowser, spray tank, or water buffer tank — is a portable or static container used to store water for feeding into a pressure washer. Unlike connecting directly to a tap, this system stores a pre-filled supply of clean water that you bring to the job site. These tanks come in many forms: small 100-litre plastic tanks that fit in a van, or massive 1,000-litre IBC (Intermediate Bulk Containers) for commercial use. They’re essential for pressure washing in locations without a water connection. Definition: A water buffer tank or water supply tank for pressure washing is any vessel that holds clean water and connects to the inlet of a pressure washer — typically via a gravity feed or a booster pump — to ensure a consistent, uninterrupted flow.Why Do You Need a Water Tank for Your Pressure Washer?
Many pressure washing professionals and homeowners run into the same problem: their machine needs more water than a standard tap can deliver. Here’s why a water reservoir for pressure washers matters:- Remote locations: Farms, building sites, and rural properties often have no nearby water supply.
- Low mains pressure: If your tap pressure is insufficient, your machine starves of water and can be damaged.
- Commercial jobs: Window cleaners, contract washers, and fleet cleaners need self-contained mobile systems.
- Emergency water storage: A filled tank keeps your washing operations going during water cuts.
- Catering to high-flow machines: Industrial pressure washers can demand 20–40 litres per minute — beyond most household mains.
Types of Water Storage Tanks for Pressure Washers
1. Bunded Water Tanks (Above-Ground)
These double-walled tanks sit on the ground and are ideal for fixed washing bays. The outer wall catches any leaks, making them safe for driveways or workshop floors. Capacities range from 200L to 10,000L.2. Portable Spray Tanks / Water Bowsers
Mounted on a trailer or the back of a van, bowsers are the go-to solution for mobile pressure washing businesses. They come with their own pump, hose reel, and sometimes a pressure washer unit built in. Sizes typically range from 100L to 1,000L.3. IBC Totes (Intermediate Bulk Containers)
A popular budget-friendly option. An IBC tote holds 1,000 litres and fits in a standard pickup truck. Second-hand IBCs are widely available. They connect easily with standard fittings and are ideal for large-scale commercial cleaning.4. Small Header Tanks (Buffer Tanks)
Compact 50–200L tanks installed inline between your water supply and the pressure washer. These act as a buffer, smoothing out fluctuations in mains pressure and ensuring a steady feed to your machine’s pump.How to Choose the Right Water Tank Size
The most critical factor when choosing a water tank for a pressure washer is matching its capacity to your machine’s flow rate. Here’s a simple formula: Formula: Tank Size (litres) = Flow Rate (L/min) × Duration (minutes) Example: A 15 L/min washer running for 60 minutes needs a 900-litre tank minimum.Tank Size Recommendations by Pressure Washer Type
| Pressure Washer Type | Flow Rate (L/min) | Recommended Tank Size | Ideal Use |
| Light-duty home use | 6–8 L/min | 100–200L | Patios, cars, bikes |
| Mid-range domestic | 8–12 L/min | 200–400L | Driveways, fences |
| Semi-professional | 12–18 L/min | 400–700L | Fleet washing, farms |
| Commercial / Industrial | 18–40 L/min | 1000L+ (IBC) | Construction, contracts |
Materials: Which Water Tank Material Is Best?
Polyethylene (Poly / Plastic) Tanks
By far the most popular choice. High-density polyethylene (HDPE) tanks are lightweight, rust-proof, UV-resistant, and food-safe. They’re perfect for outdoor use and resist most chemicals. Expect a lifespan of 10–15 years with proper care.Stainless Steel Tanks
Premium and durable, stainless steel tanks are used in food-grade and pharmaceutical applications. They’re heavier and more expensive but ideal for hot-water pressure washing applications where temperature resistance matters.IBC Totes (HDPE with Steel Cage)
A practical compromise — a plastic bladder inside a steel frame. Extremely cost-effective, especially second-hand. Widely used by professional window cleaners and contract washers across the UK.| Material | Weight | Durability | Cost | Best For |
| HDPE Poly | Light | 10–15 yrs | ££ | Mobile & static use |
| Stainless Steel | Heavy | 20+ yrs | ££££ | Hot water, industrial |
| IBC Tote | Medium | 8–12 yrs | £ | High-volume commercial |
| Galvanised Steel | Heavy | 10–15 yrs | £££ | Fixed agricultural |
Top Water Tank Picks by Use Case
Best for Homeowners: Ecosure 200L Water Storage Tank Top Pick
A solid 200-litre HDPE tank with a wide-fill aperture, low-level outlet, and UV stabilisation. Fits neatly in a garage or shed. Ideal for patios, cars, and occasional outdoor cleaning.- Capacity: 200 litres
- Material: Food-grade HDPE
- Weight empty: 12 kg
- Approx. price: £75–£110
Best for Mobile Professionals: 500L Baffled Water Bowser Mobile Pro
Designed for trailer or van mounting. Internal baffles prevent water surge when moving. Comes with a 1.5″ BSP outlet fitting — compatible with most pressure washers and booster pumps.- Capacity: 500 litres
- Baffled: Yes (reduces water surge in transit)
- Outlet size: 1.5″ BSP
- Approx. price: £180–£280
Best Budget Option: Second-Hand 1000L IBC Tote Budget King
Available from online marketplaces for £20–£60, a food-grade second-hand IBC is the most cost-effective way to get 1,000 litres of water storage. Ensure it previously held food or beverage products — never chemicals.- Capacity: 1,000 litres
- Price: £20–£60 second-hand
- Outlet: 50mm butterfly valve (standard)
- Note: Check previous contents carefully
How to Set Up a Water Tank with a Pressure Washer
Setting up your water supply tank for a pressure washer correctly is crucial. Follow these steps:- Position the tank higher than the inlet: Gravity feeding works best when the tank sits at least 30–50cm above your machine’s water inlet. This ensures positive pressure without needing a booster pump.
- Connect via the correct fitting: Most pressure washers use a standard garden hose fitting (3/4″ BSP). Use a reducer if your tank has a larger outlet.
- Install a filter: Fit a 100-micron inline strainer between the tank outlet and the machine inlet. This catches debris that can damage the pump.
- Check for air locks: Briefly open the tank outlet and let water flow freely before connecting to the pressure washer. This purges any air in the line.
- Add a booster pump if needed: If gravity feed isn’t sufficient, a small 12V or 240V booster pump ensures your pressure washer’s demand is always met.
Full Comparison: Best Water Tanks for Pressure Washers 2025
| Tank | Capacity | Material | Mobile? | Price Range | Rating |
| Ecosure 200L | 200L | HDPE | Limited | £75–£110 | ⭐⭐⭐⭐½ |
| 500L Baffled Bowser | 500L | HDPE | Yes | £180–£280 | ⭐⭐⭐⭐⭐ |
| IBC Tote (new) | 1,000L | HDPE + Steel | Yes (forklift) | £150–£250 | ⭐⭐⭐⭐ |
| IBC Tote (used) | 1,000L | HDPE + Steel | Yes (forklift) | £20–£60 | ⭐⭐⭐½ |
| 100L Buffer Tank | 100L | HDPE | Yes | £35–£70 | ⭐⭐⭐⭐ |
| Stainless 500L | 500L | Stainless | No | £500–£900 | ⭐⭐⭐⭐⭐ |
Expert Tips for Better Pressure Washing Performance
Tip 1: Use a Baffled Tank for Mobile Use
If you’re transporting water in your van or on a trailer, always choose a baffled tank. Internal baffles prevent water from sloshing violently when you corner or brake — protecting your vehicle and improving safety.Tip 2: Elevate Your Tank Whenever Possible
Even 50cm of height difference between tank outlet and machine inlet creates positive head pressure — reducing strain on your machine’s pump and preventing dry-run damage.Tip 3: Always Filter Your Water Supply
Even clean tank water can contain particulates after storage. A simple 100-micron inline filter (also called a suction strainer or sediment filter) protects your pump seals and nozzles from premature wear.Tip 4: Clean Your Tank Regularly
Algae, biofilm, and mineral deposits build up inside water tanks over time — especially in warm weather. Flush and rinse your tank every 2–4 weeks. For a thorough clean, use a food-safe tank cleaning solution followed by a full water flush.Tip 5: Match Flow Rate, Not Just PSI
Many buyers focus only on pressure (PSI or bar) but overlook flow rate (LPM or GPM). Your tank must be large enough to supply water at the rate your machine demands — otherwise pressure fluctuates and pump life drops. Expert Quote: “The number one mistake I see is professionals buying underpowered tanks. A 15 LPM machine running for an hour needs 900 litres minimum — most people guess 200L and wonder why their machine keeps cutting out.” — Mike Tanner, ProWash Equipment SpecialistFrequently Asked Questions (FAQs)
What size water tank do I need for my pressure washer?
Multiply your machine’s flow rate (in litres per minute) by the number of minutes you plan to run it. A 10 LPM machine running for 30 minutes needs at least 300 litres. Always add 20% extra capacity as a safety buffer.Can I use a pressure washer directly from a tank without a booster pump?
Yes — if you position the tank at least 30–50cm above the machine’s inlet, gravity feed provides enough pressure for most domestic and semi-professional machines. For high-demand commercial washers, a booster pump is recommended.Is an IBC tote safe to use for pressure washing water?
Yes, provided it previously held food-grade products (like fruit juice or drinking water). Never use an IBC that contains chemicals, oils, or industrial liquids — even after cleaning, residues can remain and damage your pump or contaminate surfaces.How do I connect a water tank to a pressure washer?
Most pressure washers use a standard 3/4″ BSP inlet. Fit a corresponding hose from the tank outlet to the machine’s inlet. Use a 100-micron inline filter between them. If your tank outlet is larger (e.g., 2″ IBC valve), use a BSP reducer fitting.How often should I clean my pressure washer water tank?
Every 2–4 weeks during active use, or whenever you notice discolouration or odour. Flush thoroughly with clean water. In warmer months, algae growth accelerates — so inspect more frequently and keep tanks covered to block sunlight.What is the difference between a water bowser and a water tank?
A water bowser is a trailer-mounted or mobile water storage unit that often includes its own pump, hose reel, and sometimes a pressure washer. A water tank is simply the storage vessel — it may or may not have built-in pumping equipment. Bowsers are designed for mobility; tanks can be static or mobile.Can a water tank improve my pressure washer’s performance?
Absolutely. A properly sized tank ensures your machine receives a constant, adequate water supply — eliminating pressure fluctuations caused by low mains flow. This protects your pump, maintains consistent cleaning power, and extends equipment life.Final Verdict: Which Water Tank Should You Buy?
Choosing the right water tank for your pressure washer comes down to three factors: your machine’s flow rate, how mobile you need to be, and your budget.- Homeowners with occasional needs → A 200L HDPE tank on a stand
- Mobile pressure washing businesses → A 500L baffled bowser for van or trailer
- High-volume commercial operators → A 1,000L IBC tote (new or quality used)
- Low-mains-pressure homes → A 100–200L inline buffer tank with booster pump
I’m Waqar Khan, the founder of Water Tank Guides. I have spent years researching water tank cleaning, maintenance, and installation to help homeowners protect their water supply. My mission is to provide simple, practical, and trustworthy guides that anyone can follow — no technical background required.