A buffer tank, often called a water tank or supply tank, is a crucial component in pressure washing systems, providing a consistent and adequate water supply to the pressure washer, especially when the municipal or source water flow is insufficient. It essentially acts as a reservoir, preventing the pressure washer pump from starving for water, which can lead to costly damage.
The Core Function of a Buffer Tank
The primary role of a buffer tank is to bridge the gap between an inconsistent or low-volume water source and the high-volume demand of a pressure washer. Pressure washers, especially commercial-grade units, require a specific Gallons Per Minute (GPM) flow rate to operate efficiently and prevent damage. If the incoming water supply cannot match this demand, the pump can pull air, a phenomenon known as cavitation.
Here's how it works:
- Water Collection: The buffer tank constantly collects water from your primary source (e.g., garden hose, well, pond). This inflow can be a steady stream, even if it's slow. For instance, you might have a positive flow into your tank of about seven gallons a minute.
- Storage: The tank stores this water. A typical setup might involve a 100-gallon tank, providing a substantial reserve.
- On-Demand Supply: When the pressure washer is running, it draws water directly from the buffer tank. Because the tank has a reserve, it can supply the full GPM demanded by the pressure washer, even if the incoming source water is slower than the machine's consumption.
- Float Valve Regulation: Most buffer tanks are equipped with a float valve, similar to what's found in a toilet. This valve automatically opens to refill the tank when the water level drops and closes when it's full, maintaining an optimal water level without overflowing.
This system ensures that your pressure washer always has access to the precise amount of water it needs, regardless of the limitations of the initial water hookup.
Key Benefits of Using a Buffer Tank
Integrating a buffer tank into your pressure washing setup offers several significant advantages, enhancing both the longevity of your equipment and the efficiency of your work.
- Prevents Cavitation: This is arguably the most critical benefit. Cavitation occurs when a pump draws air instead of water, creating air bubbles that collapse violently within the pump. This causes internal damage, erosion, and ultimately, premature pump failure. A buffer tank guarantees a continuous, air-free water supply.
- Ensures Consistent Water Flow and Pressure: By supplying a steady volume of water, the buffer tank helps maintain consistent pressure and flow from your pressure washer, leading to more uniform cleaning results.
- Protects Your Pressure Washer Pump: Beyond preventing cavitation, a consistent water supply reduces strain on the pump, extending its operational lifespan and reducing maintenance costs.
- Allows Use of Higher GPM Machines: If your water source only provides 4 GPM, but your pressure washer requires 8 GPM, a buffer tank allows you to operate the 8 GPM machine effectively by storing enough water to meet its demand during use.
- Flexibility with Water Sources: Buffer tanks enable pressure washing in areas with poor water pressure, low flow rates, or even where no direct hookup is available (e.g., drawing from rain barrels, ponds, or even another larger tank).
- Reduces Strain on Plumbing: Instead of demanding a high, continuous flow directly from a residential tap, which can strain older plumbing, the tank slowly refills, lessening the immediate burden on the home's water system.
Components of a Buffer Tank System
A typical buffer tank setup involves several key parts working in conjunction:
- The Tank: Available in various sizes (e.g., 50, 100, 200+ gallons) and materials (polyethylene is common for durability and chemical resistance).
- Float Valve: Automatically controls the water level, refilling the tank as water is drawn out and stopping when full.
- Bulkhead Fittings: These are watertight connectors installed through the tank walls for inlet and outlet hoses.
- Inlet Hose: Connects the primary water source to the float valve on the tank.
- Outlet Hose (Suction Hose): Connects the bottom of the buffer tank to the inlet of the pressure washer pump. It's crucial this hose is adequately sized to prevent restrictions.
- Filter/Strainer: Often integrated into the suction line to prevent debris from entering the pump.
Choosing the Right Buffer Tank
Selecting the appropriate buffer tank involves considering several factors:
| Factor | Description |
|---|---|
| Tank Size | The most crucial factor. A general rule of thumb is to have a tank large enough to supply at least 2-3 minutes of continuous operation for your pressure washer's GPM. For example, an 8 GPM machine might require at least a 24-gallon effective capacity. However, larger tanks (e.g., 100 gallons) provide a greater buffer for prolonged use or very low incoming flow rates. Remember the concept: if you have a positive inflow, like seven gallons a minute, into a 100-gallon tank, you'll have plenty of reserve. |
| Material | Polyethylene (plastic) tanks are common due to their resistance to corrosion and impact. They are also relatively lightweight. |
| Portability | Consider whether the tank needs to be easily moved. Smaller tanks might be portable, while larger ones are typically mounted on a trailer or skid. |
| Fittings | Ensure the tank has appropriate and robust bulkhead fittings for your inlet and outlet hose sizes. |
Installation and Maintenance Tips
Proper installation and maintenance are key to maximizing the effectiveness and lifespan of your buffer tank system.
- Placement:
- Position the tank as close to the pressure washer as possible to minimize suction hose length.
- Ensure the tank is elevated slightly above the pressure washer pump if possible (gravity feed), as this aids in water flow and reduces pump strain.
- Suction Line:
- Always use a reinforced, non-collapsible suction hose between the tank and the pressure washer. A standard garden hose will collapse under suction.
- Keep the suction hose as short and straight as possible, avoiding kinks or sharp bends.
- Ensure all connections are airtight to prevent air from entering the pump.
- Filtering:
- Install a screen filter or Y-strainer on the tank's outlet or before the pressure washer's inlet to catch any sediment or debris.
- Regular Cleaning:
- Periodically drain and rinse the tank to prevent algae growth or sediment buildup, especially if drawing from non-municipal sources.
- Float Valve Check:
- Ensure the float valve operates correctly, reliably refilling the tank without overflowing or getting stuck.
Practical Insights and Examples
- Commercial Applications: For professional pressure washing businesses, a large buffer tank (100-200+ gallons) is almost mandatory, especially when working on commercial properties, construction sites, or rural areas where water access or pressure might be unreliable. This allows continuous operation of high-GPM machines (e.g., 8 GPM hot water pressure washers).
- Residential Use with Low Pressure: Even for homeowners with a powerful pressure washer but notoriously low water pressure at their outdoor spigots, a smaller buffer tank can prevent the machine from struggling and extend its life.
- Soft Washing: When pre-mixing chemicals for soft washing, a dedicated buffer tank can be used to hold the mixed solution, which is then drawn directly by a dedicated pump for application, ensuring consistent dilution and availability.
By effectively managing the water supply, a buffer tank ensures your pressure washing operations are smooth, efficient, and gentle on your valuable equipment.
