Fleet operators report vehicle-cleaning emissions under Scope 3 Category 1 (purchased goods and services), calculated from supplier-specific service records where they exist and from spend or average data where they do not. The quality of that figure depends almost entirely on what the cleaning supplier can document, so the practical work is getting a per-service record, and the methodology behind it, from the supplier.
What counts as Scope 3 Category 1 for vehicle cleaning?
Category 1 covers the upstream, cradle-to-gate emissions of the goods and services a company buys, as defined in the GHG Protocol Corporate Value Chain (Scope 3) Standard. An outsourced valeting contract is a purchased service, so its footprint sits in Category 1: the cleaning products and how they were made, the water supplied and treated, the energy the supplier uses, and the supplier’s travel to the site.
The line to watch is ownership. If a fleet runs its own wash bay, the water and power are its own consumption and sit elsewhere in its inventory. Once the cleaning is bought from a supplier, those same emissions become the supplier’s, and they reach the fleet’s report through Category 1.
Which fleets have to report it under CSRD and ESRS E1 in 2026?
Fewer than were expected to a year ago. The Omnibus I Directive, published in the Official Journal on 26 February 2026, narrowed the Corporate Sustainability Reporting Directive to companies with more than 1,000 employees and more than €450 million net turnover, and removed the planned move from limited to reasonable assurance. The reporting obligation itself sits in Article 19a of the Accounting Directive, which the CSRD inserted — hence “CSRD Article 19a” in most procurement questionnaires.
For a company in scope, ESRS E1, the climate standard, requires gross Scope 3 emissions broken down by significant category. UK groups are drawn in through EU subsidiaries or EU turnover rather than directly, which is why the question often arrives at a UK fleet manager from a group sustainability team rather than from a regulator.
Being out of scope does not make the question go away. Customers, lenders and public-sector tenders ask for the same Category 1 data whether or not the law requires it.
Which calculation method should a fleet use?
The one its supplier’s data will support. The GHG Protocol’s technical guidance sets out four methods for Category 1, in rising order of accuracy:
| Method | What it needs | What it looks like for vehicle cleaning |
|---|---|---|
| Spend-based | Amount spent, times an economic emission factor | Annual valeting invoice total multiplied by a sector factor — quick, but blind to how the cleaning is done |
| Average-data | Quantity bought, times an average factor | Number of washes multiplied by an assumed per-wash water and chemical footprint |
| Hybrid | Supplier activity data plus secondary factors for the gaps | The supplier’s per-service water, product and energy figures, with DEFRA factors applied |
| Supplier-specific | The supplier’s own cradle-to-gate figure for the service | A per-service CO2e figure from the supplier, with its methodology disclosed |
Most fleets start spend-based because an invoice is all they have. The GHG Protocol Scope 3 Standard asks companies to report what share of their Scope 3 figure was calculated from supplier data, so moving a cleaning contract from spend-based to hybrid or supplier-specific shows up in the disclosure itself.
Why does a traditional wash leave gaps in the figure?
Because nothing in the transaction records what was used on each car. The three common arrangements produce very different data:
| Wash arrangement | Water per vehicle | Discharge | What the supplier can document |
|---|---|---|---|
| Automated tunnel or jet wash | Varies with cycle, pressure and reclaim | To drain or trade effluent | Usually an invoice only |
| On-site hand or pressure wash | Varies, rarely metered per car | Usually to drain | No per-vehicle record |
| Mobile waterless valet | No mains wash water used on site | None from the service | A per-service record |
With a water-fed wash the fleet has to assume a volume per car, and that assumption is multiplied across every vehicle and every visit. Our comparison of petrol-station washes for CSRD fleets looks at why a pay-per-use bay cannot be audited at all.
Which DEFRA factors apply to water used in a wash?
DEFRA’s 2026 GHG Conversion Factors for Company Reporting put water supply at 0.1913 kgCO2e per cubic metre and water treatment at 0.17088 kgCO2e per cubic metre. Use the factor set for the year you are reporting: the 2024 set, for example, has 0.15311 and 0.18574.
The worked figure is small. A wash that uses 150 litres (0.15 cubic metres) carries 0.15 × (0.1913 + 0.17088) = 0.054 kgCO2e for supply and treatment. Water is rarely the largest part of a cleaning contract’s Category 1 footprint; the products and the supplier’s energy and travel usually matter more. The case for a waterless supplier is less about a large carbon saving on water and more that the figure stops being an estimate.
Can water avoided be deducted from the Scope 3 figure?
No. A waterless service’s Category 1 footprint is its own products, energy and travel, reported as a gross figure. Water that a conventional wash would have used is an avoided emission, and the GHG Protocol requires avoided emissions to be reported separately from the inventory, never netted off it.
That is why MMCC reports litres of water conserved against a traditional wash baseline as a separate, labelled estimate, alongside the CO2e estimate rather than subtracted from it. How that water figure is used in its own right is covered in turning water savings into ESG data.
What should a valeting supplier give you for the audit trail?
A record per service, the numbers derived from it, and the method behind the numbers. Limited assurance means an assurer will trace a sample of figures back to source, so each of these has to exist:
- Per-service record: date, service type, technician and the vehicle’s inspection result, from the same 20-point check that produces a Vehicle Health Check report
- Environmental estimates: CO2e in kilograms, energy in kWh, and water and wastewater avoided in litres, each marked as an estimate
- Methodology notes: the baseline used, the factors applied and their year
- An export: a downloadable report, so the figures reach your ESG platform without retyping
These are the fields the ESG Impact module on our Corporate fleet services page carries for every service, with methodology notes behind each number. Figures vary with vehicle mix, service tier and site, which is exactly why the notes matter. The records are the same whether the visit is mobile car valeting in Esher or at a staff car park served by our Weybridge mobile valeting round. Which of those claims hold up in a report is covered in the sustainability claims a fleet can evidence.
Fleet managers can request a sample Scope 3 data export by booking a Fleet Readiness Audit.