How to choose a wash bay for your business

Cleanawater on 15 June 2016

Wash bays are required by many Australian businesses in order to achieve water authority compliance.

How do you know if your business needs a wash bay? Well, if your business is washing vehicles or equipment and is thereby producing wastewater, then you need a wash bay. It doesn't matter if washing is infrequent or regular. If you're washing vehicles or equipment on your business' premises, then you require a wash bay to be water authority compliant.

Fortunately, wash bays come in a variety of shapes and sizes to suit a variety of needs and businesses. In this article we will examine each, to determine which is suitable for your commercial operation. To learn more about the specific applications of wash bays for different industries, watch the video below.


What is a compliant wash bay?

roofed wash bays covered

A wash bay is a cleaning station, located on a business' premises. It is used to clean vehicles and equipment, while also safely disposing of wastewater.

Wash bays can be temporary or permanent structures. They can also be open or roofed. Each type of wash bay features advantages and limitations.

Which type of wash bay is appropriate depends on the needs and circumstances of each business. To be water authority compliant, a wash bay will need some or all of the following components:

  • Pre-treatment device
  • Oil separator
  • Silt trap
  • Perimeter bunding
  • Holding pit
  • First flush diversion system

Exact requirements do differ between states and territories. However, broadly speaking, these are the components needed to achieve water authority compliance.

Short term use: Temporary wash bays

Temporary wash bays are, as the name suggests, non-permanent structures that are ideal for non-permanent workplaces. They are commonly used on construction sites and on building developments. However, they can be used for any job that requires short term infrastructure.

Manufacturers make temporary wash bays for temporary use. Therefore, they do not require the complex components associated with permanent structures. This makes temporary wash bays faster and cheaper to install than permanent wash bays.

"Many businesses in Australia require wash bays to achieve water authority compliance."

Long term use: Permanent wash bays

permanent wash bay2

Manufacturers build permanent wash bays to stand the test of time. Properly maintained, these wash bays can provide years, or even decades of use.

Businesses with fixed locations often install this type of wash bay. It's common to see permanent wash bays in mechanic's workshops, mining sites and service stations.

As permanent wash bays are steadfast structures, they can be more time-consuming and expensive to install compared to a temporary wash bay. However, they may prove more economical in the long term, as they provide a much longer lasting solution.

Permanent wash bays are regularly the best choice for businesses with fixed premises.


Temporary wash bays

Permanent wash bays

Price of installation


Speed of installation


Permanent solution


Recommended for fixed locations


Open top use: Open wash bays

unroofed wash bays

Wash bays can be either roofed or unroofed (open). Both options provide unique benefits.

The main advantage of an unroofed wash bay is price. Erecting a roof can be costly. It requires extra materials, labour and permits. With an unroofed wash bay, you can avoid these things and their associated costs.

A secondary benefit is speed. Roofed wash bays require building permits. Whereas unroofed wash bays generally do not. This combined with a briefer installation, can save you a significant amount of time.

Thirdly, because a roof is not present with this type of wash bay, vertical space is not limited. This means you can use it to wash oversized vehicles like cranes and heavy equipment.

When should an unroofed wash bay not be used?

Unroofed wash bays uncovered by design. That can make washing vehicles in harsh conditions difficult, uncomfortable or even impossible.

If your business' location regularly experiences dense storms or extreme temperatures, then a roofed alternative may be a more suitable solution.

Additionally, unroofed wash bays may require the installation of a first flush diversion system. It is important to factor in this cost when choosing between a roofed and unroofed wash bay.

"Wash bays can be either roofed or unroofed. Both options provide unique benefits."

All-weather use: roofed wash bays

With a roofed wash bay, you can wash vehicles in just about any weather—rain, hail or shine.

When compared to their unroofed counterparts, roofed wash bays tend to be more expensive to install. They usually feature lengthier construction times too. This is because additional materials, labour and permits are all required to construct the roof.

The upshot of this is that once installed a roofed wash bay can provide 'all-weather' cleaning. Because the roof stops heavy rain and direct heat from the sun, you can clean in nearly all conditions. Therefore, you won't have to hold off on cleaning because of storms or summer heat.

Another benefit of unroofed wash bays is that, because stormwater runs off of your roof, you will most likely not require additional equipment to handle stormwater which has been contaminated by wastewater. This could save you the cost of a first flush diversion system.

When should a roofed wash bay not be used?

A roof naturally limits the height of your wash bay. If you are cleaning large vehicles such as cranes or heavy equipment, you will have to install a suitably raised roof. If this option is not viable, an unroofed wash bay may be a more practical alternative.



Unroofed wash bays

Roofed wash bays

Price of installation


Speed of installation


All-weather use


First flush diversion system (often) not required


Ideal for cleaning over-sized vehicles


Want to know more about wash bays? Cleanawater are the Australian specialists in wastewater and water authority compliance. Our expert team can help you to find, select and install a wash bay that is your right for your industry and your business.

Contact us today to talk water authority requirements, installation procedures or pricing.