Wastewater from Car Washes and Service Stations
Stricter rules, inspections, and penalties
Wastewater from car washes and vehicle service centres cannot be discharged without meeting the rules for treatment and disposal because it may contain oils and other pollutants. The operator must have the required permit or arrangements with the sewer operator and keep the necessary records. This article explains how to organise wastewater handling so the business can meet its duties during normal operation and inspections while reducing the risk of penalties.
Key takeaways
Why supervision of car washes and auto repair shops is becoming stricter
An amendment to the Water Act, the so-called emergency amendment, has tightened the rules for reporting accidents and increased the upper limits of some penalties. The emphasis is on ensuring that the polluter can be traced and held fully responsible. For operators, this means one thing: having their administration in order and technology that actually works.
The lawyers at ARROWS law firm have long been dealing with cases of companies that have come into conflict with the water authority or the Czech Environmental Inspectorate (CEI). We know that prevention and correctly set processes are always cheaper than subsequently dealing with penalties and litigation.
How the law defines wastewater from your operations
The basic regulation is Act No. 254/2001 Coll., on Waters (the Water Act). Wastewater is water used in residential, industrial, agricultural, and other buildings or facilities, if its quality has been altered. In the context of car washes and auto repair shops, this mainly includes:
Water from washing vehicles – contaminated with petroleum substances, detergents, and mechanical impurities.
Water from cleaning workshop floors – may contain drips of operating fluids.
Process water – e.g., from degreasing parts.
Sanitary wastewater – from employee social facilities.
The law strictly prohibits discharging this water freely into the terrain, into soakaways, or directly into watercourses without the appropriate permit and treatment. Even discharging into the public sewer system is subject to strict rules.
Emission limits and where you discharge water
Your obligations vary depending on where you discharge the wastewater. There are three main options that determine the technical and administrative requirements for your operation.
Discharging into the public sewer system
This is the most common case. You are subject to the Act on Water Supply and Sewerage Systems.
Obligation: You must have a written contract with the owner or operator of the sewer system.
Limits: You must comply with the pollution limits set out in the sewerage regulations of the given municipality.
Technology: To meet the limits, it is usually necessary to install a petroleum substance separator (oil separator).
Discharging into surface waters (stream, river)
If a sewer system is not available, you discharge water into a watercourse.
Obligation: You must have a valid permit to discharge wastewater from the water authority.
Limits: They are set directly in the permit and are based on government regulations.
Technology: A simple separator is not enough here; a biological wastewater treatment plant (WWTP) with tertiary treatment is usually required.
No-drainage sump (cesspit)
If you do not discharge anywhere, you collect the water.
Obligation: The sump must be watertight, and you must have a leakproof certificate.
Disposal: You do not have a discharge permit, but you must prove the disposal of wastewater, i.e., documents on removal by a vacuum truck to a WWTP.
Exceeding the limits, whether sewerage or legal, is strictly penalized, and the CEI also inspects small operations.
Obligations of car wash and auto repair shop operators
Operators must fulfill a number of administrative and technical obligations.
Permits and contractual relationships: You must have either a permit to discharge into surface or groundwater, or a valid contract for wastewater disposal into the sewer system. Pay attention to the validity of the permit, which is often issued for a limited period.
Operation of the treatment facility: The facility must be operated according to the operating manual. This means regular inspections, cleaning of filters, pumping out sludge and separated oil. You must keep an operating log of maintenance.
Measurement and quality control: If you have a permit to discharge into water, you have a legal obligation to have samples analyzed by an accredited laboratory. The results are submitted to the water authority, often electronically via the ISPOP system.
Management of waste from treatment: Oil, sludge, and sand captured in the separator are hazardous waste. You must have a contract with an authorized company for their disposal and keep a continuous record of waste.
Handling accidents: Every operation working with substances hazardous to water must have an approved Emergency Plan. In the event of a leak, it is necessary to immediately inform the Fire Rescue Service and the water authority or the CEI.
Treatment technology – a necessary investment
Without the right technology, the limits cannot be met. The equipment must comply with ČSN (Czech Technical Standards) and be certified.
Petroleum substance separators (Oil separators): Gravity and coalescence separators are the basis for car washes and repair shops. They separate oil from water and require regular service.
Biological WWTPs: Necessary when discharging into watercourses. They use bacteria to break down organic pollution.
Water recirculation: Modern car washes use recirculation systems that return the treated water back to the washing process.
The investment in technology ranges from tens to hundreds of thousands of crowns, but it is essential for legal operation. The lawyers at ARROWS can assist in reviewing contracts with technology suppliers and ensuring performance guarantees.
Inspections and fines – what you need to know
The Czech Environmental Inspectorate (CEI) conducts both planned and random inspections, often based on public complaints. Inspectors check the validity of water management permits, compliance with emission limits, and the condition of technical equipment.
They also focus on operating logs and records of waste disposal, such as sludge and oils. Proof of the watertightness of sumps and pipes is also required.
Amount of fines under the Water Act:
Discharging without a permit: For legal entities and self-employed individuals, up to CZK 10,000,000.
Exceeding emission limits: The upper limit for legal entities is up to CZK 5,000,000.
Failure to report an accident: Up to CZK 500,000, in serious cases up to CZK 5,000,000.
Neglecting records and measurements: Up to CZK 500,000.
If the inspection finds a serious error, it can, in addition to a fine, also order the suspension of operations until the situation is rectified.
Risks and penalties | How ARROWS helps (consultation@arws.cz) |
Discharging without a permit / into a soakaway: Fine up to CZK 10,000,000, threat of shutdown, obligation to remove the illegal outlet. | We will analyze your situation, arrange for project preparation, and represent you in proceedings for a retroactive permit or a change in the method of water management. |
Exceeding limits in samples: Penalty from the CEI, increased fees for discharge. | If you are facing a fine, we will verify the correctness of the sampling and the laboratory's procedure. |
Missing documentation (logs, certificates): Fine for administrative offenses (up to CZK 500,000). | We will set up a record-keeping system for you so that you can pass an inspection. |
Accident and substance leak: Fine for failure to report, obligation to remediate (clean up) soil and water, which can cost millions. | In the event of an accident, we will provide you with legal support in negotiations with the authorities to minimize the impacts and penalties. |
Dispute with the sewer system operator: Threat of contract termination and disconnection from the sewer system. | We will represent you in negotiations with the waterworks company about the conditions of discharge and amendment of the sewerage regulations or contract. |
Monitoring and record-keeping obligation
The amendment to the Water Act and related regulations place greater emphasis on monitoring. While the obligation for continuous online measurement primarily concerns large industrial polluters, smaller operations must also be more vigilant.
The obligation to measure the volume and quality of discharged water stems directly from the discharge permit. If you discharge into surface waters, you must have a measuring object installed and regularly take samples.
For high-risk operations, authorities may more frequently require the installation of automatic samplers or sensors, especially if the operation is located in a protected area or near water supply sources.
Ignoring the measurement obligation or falsifying results is one of the quickest ways to attract the attention of the inspectorate. The lawyers at ARROWS monitor the interpretation practice and will help you set up a system that complies with current requirements.
Conclusion
The issue of wastewater from car washes and auto repair shops is a complex intersection of technical standards and legal regulations. Neglecting obligations can lead to ruinous fines.
Basic rules for an operator's peace of mind:
Have a valid permit or a sewerage contract.
Have a functional treatment facility and take care of it.
Keep flawless records and carry out prescribed measurements.
Handle accidents immediately and transparently.
The lawyers at ARROWS law firm have extensive experience with Czech water law and representing clients before the CEI. Whether you are dealing with a new permit or defending against an imposed fine, we are ready to help you.
Don't wait for an inspection; prevention is cheaper. Write to us at consultation@arws.cz and we will outline the possible solutions for your situation without obligation.
About the author
Disclaimer:
The information contained in this article is for general informational purposes only and serves as a basic guide to the issue as of 2026. Although we strive for maximum accuracy, laws and their interpretation evolve over time. We are ARROWS Law Firm, a member of the Czech Bar Association (our supervisory authority), and for the maximum security of our clients, we are insured for professional liability with a limit of CZK 350,000,000. To verify the current wording of the regulations and their application to your specific situation, it is necessary to contact ARROWS Law Firm directly (consultation@arws.cz). We are not liable for any damages arising from the independent use of the information in this article without prior individual legal consultation.