Wastewater and Sludge Guidelines
This is the new version of Wastewater & Sludge Guidelines
This version (V2) is published and available to prepare for. It will replace the active version (V1) and take effect from 01 Nov 2026. Until then, continue using Wastewater & Sludge Guidelines V1. View Changelog
Wastewater and sludge quality management ensures the effective identification, monitoring and control of pollutants throughout production processes.
It contributes to cleaner water systems, reduces environmental impact, and supports the transition to more sustainable and responsible manufacturing.
Scope for Wastewater and Sludge Guidelines
ZDHC is not a mandatory requirement, but it helps align with multiple brand-specific testing and monitoring requirements for wastewater and sludge. Some parameters also support suppliers in meeting broader industry expectations and sound environmental practices. However, meeting the parameters below does not automatically ensure compliance with any other external standards or regulations.
The guidelines apply to discharged industrial wastewater and sludge produced from wastewater treatment operations of textile, apparel, leather and footwear suppliers with wet processing facilities. This includes, but is not limited to:
- Dyeing and finishing of fibres, yarns, threads, fabrics, garments, textile trims and laces
- Fabric mills
- Laundry, washing and finishing facilities
- Printing facilities
- Raw wool scouring
- Vertical finished goods manufacturing facilities where any wet processes occur
- Synthetic materials (synthetic fibres or textile-polymer composite microfibres) coated with PU, PVC or similar polymers that hold the appearance of leather but are not made from animal skin or hide.
- Any supplier who discharges to a central effluent treatment plant (CETP) is deemed an indirect supplier and should test against these guidelines.
- With reference to leather:
- Raw materials include: Hides from animal origin.
- Facility type tanning process includes:
- Beamhouse and tanning: Including soaking, liming, removal of extraneous tissues, unhairing and fleshing, deliming, bating, pickling, pre-tanning, etc.
- Wet-end, crusting and/or finishing: Such as washing, degreasing, re-tanning, dyeing, fat liquoring, oiling, coating etc.
The ZDHC Wastewater and Sludge Guidelines do not currently apply to wastewater discharge from suppliers including, but not limited to:
- Accessories or trim manufacturers e.g. zips, buttons (plastic metal, glass, shells etc ) and galvanising processes
- Cotton farming
- Cattle ranching
- Polymer production
- Production of chemicals or mixing of chemical formulations for commercial sale
In addition, the ZDHC Wastewater and Sludge Guidelines do not currently apply to:
- Discharge of domestic wastewater only. Such as:
- From a sewing/garmenting (e.g. staking) facility that employs workers but has no in-house wet processing unit.
- Domestic wastewater that is not blended with industrial wastewater.
- Wastewater management and treatment systems beyond the property boundaries of the supplier. This includes any third-party, off-site, centralised or common effluent treatment plants (CETP) that are not under the direct control and/or ownership of the supplier.
- CETPs can choose to monitor their performance against these guidelines.
- With reference to leather:
- Slaughter houses
- Leather facilities with only mechanical processes/phases e.g. only embossing, polishing, staking or dry milling.
Separate wastewater requirements are available for Man-Made Cellulosic Fibres (MMCF), Dissolved Pulp, Recycled Polyester Fibre.