What you need to know before building a car wash bay

Cleanawater on 1 February 2021

Building a car wash bay seems like a simple undertaking at first glance. But the realities are a little more complicated due to the regulations surrounding wastewater discharge. Only an expert in the industry that understands the conditions and regulations in Australia can guide you through the process of building a car wash bay.

Not only that, but there are also several options to consider. Do you want a permanent or portable installation? Do you want to recycle water or discharge all water to the trade waste sewer system? What are the requirements for a compliant car wash bay?

Cleanawater offers expert products and services to help you install a compliant and effective car wash bay.

Portable versus permanent

Before starting a car wash bay project, you need to decide whether you want a permanent installation or not.

Permanent wash bays are cheaper to install, but they require civil construction to implement. It makes sense that these permanent installations are used for long term facilities where there is no risk of losing the investment due to a location move. If the site is leased, the owner will need to give permission for the construction work.

Portable wash bays offer the benefits of being easily movable. Even though they are more expensive to implement, the investment will not be lost if the owner moves to a different location. As there is no civil construction to install a portable structure, there is no need to obtain special permission

Main components of a car wash bay

A car wash bay's critical functions are to contain the water used for washing and remove pollutants from the wastewater.

Car wash bays have a solid surface for cars to stand on during washing. A permanent structure may have a concrete or asphalt base with bunded edges to prevent water from seeping into the ground or flowing into a stormwater sewer. A portable wash bay has a floor made of galvanised steel sheet and sidewalls to contain water splashes.

Used water must be stored before pumping to the treatment system. Permanent wash bays have a collection pit below ground for this purpose. Wastewater accumulates until the level rises to the point where the pump switches and empties the pit into the treatment system. Portable wash bays collect used water in specially designed troughs.

Processing wastewater has two steps. First, there is the removal of solids in a silt trap. This step is essential to prevent damage or blockages in downstream treatment equipment. Second, there is the removal of oil. An oil water separator performs this function using coalescing plates. The oil collects in a waste oil container for disposal. In some conditions, it may be necessary for another step of water treatment (for example, pH) before the water is acceptable for release to trade waste.

Large wash bays (larger than 20 square meters) must be roofed or have rain diversion systems installed. This is to protect the municipal water treatment plants from being overloaded. Rain diversion systems divert rainwater to the stormwater sewer after an initial flush of the wash bay pad.

Trade waste compliance

The trade waste sewer network is controlled by local water authorities. No one may discharge to this network without permission in the form of a trade waste license. Each local authority has a process for obtaining a trade waste license. They specify conditions that the permit holder must adhere to. Failure to comply with trade waste regulations could result in fines and even business closure until the situation is rectified.

Find out more about liquid trade waste regulations for New South Wales.

Recycle water or discharge to effluent

 unroofed wash bay with wastewater treatment

Car wash bays use high volumes of water. However, recycling options mean that this water can be re-used many times over. Water recycling is beneficial to the environment because it reduces municipal water demand. This also lowers the operating costs of a wash bay. Recycling systems use filters to clean the water before re-use. Cleanawater experts can help you identify which filtration system is the right solution for your needs.

It is typical for recycling systems to re-use 80% to 90% of the collected water due to evaporation losses. Recycling systems can be installed on a fixed price or pay-as-you-go service. This allows car wash operators to plan their cash flow in the way that best suits their business.

Because wash bays cover a large surface area, rainwater harvesting is also a viable option. Putting a roof over the wash bay and then collecting rainwater in tanks yields a significant freshwater supply for the operation.

Talk to Cleanawater for expert advice

Contact Cleanawater for expert advice about building a car wash bay. Our technical experts help you through each step of the process, from applying for a trade waste permit to choosing the right wash bay solution for your needs.

Contact Cleanawater to find out more about our permanent and portable wash bays.