Standards Development

Scope

This document provides guidelines for the safe, sustainable, and standardized use of urban reclaimed water for vehicle washing. It specifies requirements for water quality, supplemental treatment by water suppliers, onsite treatment and onsite reuse of vehicle washing wastewater, operation management, monitoring, and emergency response. This document is applicable to:

— The use of centralized urban reclaimed water for washing various vehicles in urban areas, including passenger cars, commercial vehicles, public transport buses, trains, subways, urban rail transit, aircraft, and other motorized and nonmotorized vehicles.

— The supplemental treatment, terminal disinfection, and quality control of reclaimed water at vehicle washing sites.

 — The design, construction, operation, and maintenance of onsite vehicle washing wastewater reuse systems.

This document considers graded requirements based on personnel exposure risk and washing methods, and applies to both external centralized reclaimed water supply and onsite wastewater recycling systems.

This document is not applicable to Industrial vehicle washing involving hazardous pollutants that require specialized treatment.

Purpose

Driven by rapid urbanization and economic development, the number of transportation vehicles including passenger cars, commercial vehicles, railway rolling stocks, civil aircraft, urban rail transit and other means of transport has been increasing continuously worldwide. As a result, the demand and water consumption for vehicle washing service are expected to keep rising steadily in the future. Vehicle washing, as a typical highfrequency, largevolume urban nonpotable water application scenario, is highly suitable for using reclaimed water due to its stable demand and controllable process. However, the use of reclaimed water for vehicle washing may bring a series of risks. Workers, operators and vehicle users may be exposed to pollutants and pathogenic microorganisms in reclaimed water through direct skin contact, splashing or inhalation, leading to potential health hazards. Unsuitable water quality may also cause corrosion, scaling, clogging and biofouling of washing equipment and pipelines, shortening the service life of facilities. In addition, excessive turbidity, colour, oil, total dissolved solids and metal ions may leave stains, water spots, residues or discoloration on vehicle surfaces, impairing cleaning performance and damaging surface materials. Furthermore, human exposure levels vary significantly among different washing modes: full manual washing involves prolonged and extensive direct contact with water, representing high exposure risk; semiautomatic washing involves occasional and limited partial contact, representing low exposure risk; while fully automatic washing involves almost no operational water contact, representing negligible exposure risk. Therefore, differentiated risk control and water quality requirements are necessary for different washing practices.

Vehicle washing wastewater usually contains oil, surfactants, suspended solids, sediments and other contaminants. Direct discharge of such wastewater without proper treatment will pose adverse impacts on soil, surface water and groundwater, and undermine urban ecological environment. On the other hand, vehicle washing wastewater can be collected, treated and recycled onsite for repeated washing operations, which greatly reduces freshwater intake and improves overall water use efficiency. For this reason, it is essential to establish standardized onsite vehicle washing wastewater reuse systems with proper collection, pretreatment, treatment and disinfection processes.

This document establishes uniform technical and management guidelines for the safe and sustainable application of urban reclaimed water in vehicle washing, covering general recommendations, water quality considerations, supplier supplemental treatment, onsite treatment and disinfection, onsite wastewater reuse, operation monitoring, pipeline and facility management, personnel training and emergency response. It aims to protect human health, prevent equipment damage and vehicle surface impairment, avoid negative environmental impacts, enhance public acceptance, lower freshwater dependence and support the orderly and largescale promotion of urban water reuse. This document follows the fitforpurpose principle, classifies exposure risks according to full manual, semiautomatic and fully automatic washing modes, specifies graded water quality parameters and monitoring frequencies, and references relevant ISO water reuse standards to provide consistent, practical and globally applicable requirements for water utilities, vehicle washing operators, equipment suppliers, supervision authorities and other stakeholders.