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GRI 303: Water and Effluents · 2018
Disclosure GRI 303-4

Water discharge

Practical guidance for preparing this disclosure. Use this card to identify datapoints, verify claims and organise supporting evidence. For exact requirements, always refer to the official GRI source.

Dr Ross Kurinko, GRI Certified Trainer
Reviewed by Dr Ross Kurinko · GRI Certified Trainer LRA educational guidance · Not issued or endorsed by GRI
To prepare this disclosure
Disclosure focus

This disclosure asks an organisation to explain where its water is discharged and how much is discharged, rather than only describing water use in general. The focus is on the organisation’s own operations and the places where water leaves those operations, so the report should make clear what discharges are included, what is excluded, and whether the information covers the whole organisation or only selected sites.

In practice, the key point is coverage and clarity: readers should be able to see whether discharge data comes from all relevant facilities, a defined group of sites, or just a few locations, and understand the basis used to measure it. If some operations are not included, the organisation should make that limitation clear so the disclosure does not give a misleading picture of its overall discharge profile.

This LRA educational guidance supports disclosure preparation. For the exact requirements, always refer to the official GRI source.

Before you start

A quick mental checklist before you prepare this disclosure — tick each as you settle it.

Preparation

Key datapoints to prepare

Datapoint What to capture Evidence hint Owner
Total discharge volume The full volume of water released from operations into any receiving area during the reporting period, expressed as one total figure. Water balance or discharge register, site meter logs, wastewater invoices, and period-end consolidation. Environment / Facilities
Discharge by destination A breakdown of the total discharge volume by where the water went, using the organisation’s chosen destination categories. Environmental reporting workbook, discharge register, and site-level classification notes for each outlet or receiving area. Environment / Sustainability reporting
Third-party water transfer Whether any water supplied by another party is passed on to other organisations for their use, recorded as a yes/no response. Utility contracts, water supply and resale records, site operations logs, and commercial arrangements with counterparties. Operations / Procurement
Third-party water volume The amount of water received from another party and then sent on to other organisations for use, for the reporting period. Meter readings, transfer logs, invoices, and any resale or onward-supply records. Operations / Finance
Discharge by category A breakdown of total discharge volume by the organisation’s internal discharge categories, as used in reporting. Environmental data system, site discharge schedules, and the category mapping used in consolidation. Environment / Reporting
Stress-area discharge total The total volume of water discharged from locations identified as water-stressed during the reporting period. Site location list, water-stress screening or mapping, discharge records, and consolidation workbook. Environment / Site management
Stress-area discharge split A breakdown of discharge volume from water-stressed locations by the organisation’s reporting categories. Water-stress site register, discharge data by site, and the category mapping used for the split. Environment / Sustainability reporting
Substances treated The named substances of concern for which discharge treatment is applied before release. Treatment plant specifications, permit conditions, laboratory results, and the list of substances covered by treatment controls. Environment / Compliance
Substance definition basis A plain explanation of how the organisation decided which substances count as substances of concern for this disclosure. Internal methodology note, risk assessment, compliance register, and any substance screening criteria. Environment / Compliance
Reference list used Any external standard, recognised list, or internal criteria used to decide which substances are treated as substances of concern. Methodology paper, policy note, regulatory references, and links or extracts from the list or criteria applied. Environment / Compliance
Limit-setting method How discharge limits were set for the substances of concern, including the basis used to choose each limit. Permit documents, internal standards, engineering calculations, and approval records for limit setting. Environment / Compliance / Engineering
Breach count The number of times discharge limits were not met during the reporting period, counted as incidents. Incident log, compliance register, laboratory exceedance reports, and corrective action records. Environment / Compliance
Compilation notes Any extra context needed to understand how the figures were assembled, including scope, methods, assumptions, and key exclusions. Reporting methodology, consolidation notes, boundary memo, and any assumptions log or data-quality commentary. Sustainability reporting / Finance
＋ Show GRI 303-4 sub-elements (LRA working checklist)

How to prepare it

1Set the reporting boundary first: decide which sites, operations and time period are in scope, and make sure the same boundary is used across every figure and narrative in this disclosure.
2Agree the definitions before you calculate anything: specify what you will count as a discharge destination, how you will group destinations and categories, and how you will identify water-stressed locations for the relevant totals.
3Gather the source records that support each required item: meter readings, discharge logs, treatment records, incident records, and any internal or external documents used to classify priority substances, set limits, or confirm whether water was passed on to another organisation for use.
4Compile the reported outputs in a way that matches the data type for each item: enter the overall discharge total, break it down by destination type and by category, show the subset linked to water-stressed areas with its own breakdown, and provide the required narrative on priority substances, limit-setting, and any non-compliance count.
5Explain any exclusions, estimation methods, boundary changes, reclassifications or other choices that affect comparability, and include enough context for a reader to understand how the numbers and descriptions were built.
6Check the final draft against the official source and your evidence pack: confirm every required item is covered, the labels and groupings are consistent, and the reported figures and narratives align with the underlying records before sign-off.
Request the data

Request the discharge and treatment data from site operations

Translate the disclosure into an internal business question — then adapt it to your organisation's own language.

What water leaves our sites, where does it go, how is it grouped, and what treatment, limit-setting, and breach records support the figures?

Use your organisation’s own site, utility, treatment, and compliance terms first, then map them to the reporting fields. Keep the ask in the language your operations, facilities, and environmental teams already use, rather than using framework labels.

Weak request

Please provide the GRI 303-4 water discharge data and evidence for the reporting period.

Why it fails: It uses framework language only, so the owner has to translate the ask into their own records. It also leaves out the practical details needed to pull the right site data, the split by destination, the water-stress subset, the treatment and limit-setting basis, and the incident log references.

Better request

Please send the site water discharge pack for [period] from your operations records: totals by site, where the water went using your normal destination names, any transfer to another organisation, the water-stressed site subset, the substances you treat before release, how you define that substance list, how release limits are set, any breaches, and the source extracts plus a short note on method and assumptions.

Formal email template
Subject: Request for site water discharge data and supporting records

Hi [Name],

I’m pulling together the sustainability reporting pack and need your help with the site water discharge information for [reporting period].

Please send, for each included site/asset:
- the total volume of water leaving the site
- the destination split using your normal site categories
- any water sent on to another organisation for use, including the volume
- the subset from sites you classify as water-stressed, with the same split
- the list of substances you treat before release, plus how you define that list
- the basis you use to set release limits for those substances
- any breaches or non-conformance events against those limits
- a short note on how the figures were compiled and any assumptions or exclusions

Please also include the source files or system extracts, and confirm the period, boundary, and measurement method used.

If it helps, you can return it in the table format below. Please adapt this to your organisation’s own terminology and check the official source before sign-off.

Thanks,
[Your name]
Short Teams / Slack version
Hi [Name] — could you share the site water discharge pack for [period]? Please include totals, destination split, any transfer to another organisation, water-stressed site figures, treated substances, limit-setting basis, breach count, and a short compilation note. Use your normal site terms and send the source extract(s) too. Thanks.
Industry examples
Food manufacturing

Context. A factory network with process water, cooling water, and trade effluent records held by site engineering and EHS.

Adapted request. Please share the discharge pack for [period] for all included plants: total outflow, split by our usual outlet names (for example sewer, surface water, tanker transfer), any water passed to another business for use, the water-stressed plant subset, the treated substance list, the basis for the site release limits, and any permit or limit breaches. Include the meter exports, lab results, and the incident log reference.

Example response. Plant A: 120,000 m3 total; 90,000 m3 to sewer; 30,000 m3 to surface water; 0 m3 transferred to another business; water-stressed site yes; treated substances: ammonia, COD, suspended solids; limit breaches: 2; source files: meter export, lab report, incident log.

Data centres

Context. A portfolio with cooling system blowdown, site drainage, and environmental permit tracking managed by facilities and compliance.

Adapted request. Please provide the site discharge pack for [period] for each data centre: total discharge, split by our internal outlet categories, any volumes sent to another organisation, the water-stressed site subset, the list of substances treated before release, how that list is defined, the method used to set discharge limits, and any exceedances. Please attach the source system export and a short note on how estimates were made where meters are not fitted.

Example response. DC North: 18,500 m3 total; 16,000 m3 to foul sewer; 2,500 m3 to surface water; 0 m3 transferred to another organisation; water-stressed site yes; treated substances: pH adjustment chemicals and suspended solids; limit breaches: 0; source files: facilities dashboard export, permit tracker, monthly compliance note.

Draft your disclosure

Notes that turn data into a disclosure

LRA training templates — adapt them to your organisation, and check the official source before sign-off.

Method note

Explain how the figures were compiled, including the basis used to classify destinations, categories, water-stressed locations and priority substances, plus any external list or criteria relied on.

Context note

Set out what the totals mean in practice by distinguishing direct discharge from water passed to other organisations, and by showing how much of the discharge occurred in water-stressed areas or involved priority substances.

Fluctuation statement

If the numbers moved materially, describe the operational or site-level reasons behind the change, such as shifts in discharge routes, category mix, stressed-location activity, treatment coverage or compliance events.

Content index entry
GRI 303-4 Water discharge — [location / page] / [notes]
Download Centre

Preparation tools & forms

Professional preparation tools for GRI 303-4 — free with an LRA Community membership. Register once (it's free) and every download unlocks, together with the Disclosure Library, templates and the LRA AI-assistant.

Free · Community members
01XLSPrep & Assurance workbookDatapoints, risks, evidence to check, owner and evidence pack.Get it free ↧ 02XLSData-request packRequest email, message template, response fields and sign-off structure.Get it free ↧ 03PDFLibrary CardPrintable one-page summary of this disclosure card.Get it free ↧
Assurance readiness

For each claim, check the evidence

ClaimRiskEvidence to check
I prepared the coverage figure from the discharge records we held for the reporting period, using the same boundary and cut-off rules throughout so the total is complete and not double-counted.The assurer will test whether the figure really covers all relevant discharges, whether any sites, periods or flows were left out, and whether the boundary rules were applied consistently.['Reporting boundary note showing which operations, sites and time period were included', 'Source discharge logs or meter records used to build the total', 'Reconciliation showing the reported figure to underlying site-level data', 'Documented cut-off and consolidation rules applied before publication']
I split the reported volume using our internal destination categories, and the grouping was done from the same source dataset rather than from separate estimates.The assurer will probe whether the category split is complete, whether each discharge was assigned to only one bucket, and whether the category labels match the underlying records.['Data mapping that links source records to each destination category', 'Working paper showing the category totals add back to the overall figure', 'System extract or spreadsheet used for the classification', 'Review sign-off confirming the category split was checked before release']
Where third-party water was passed on for use by another organisation, we identified it separately and kept a clear audit trail for the volume reported.The assurer will check whether this item was correctly identified, whether the organisation had a basis for saying it was passed on for use, and whether the volume is supported by records.['Contracts, transfer notes or operational records showing the onward transfer', 'Volume calculation or meter evidence for the amount reported', 'Internal memo explaining the basis for treating the flow as third-party water sent on for use', 'Evidence of review of the classification before publication']
The amount attributed to the onward transfer was taken from the same controlled data set as the main discharge figure, with any exclusions or adjustments documented.The assurer will look for unsupported adjustments, inconsistent treatment between the main figure and this sub-figure, and weak controls over the calculation.['Calculation workbook with formulas and version control', 'List of any adjustments, exclusions or estimation steps', 'Reconciliation between the sub-figure and source records', 'Approval trail showing the figure was checked before reporting']
I compiled the category breakdown from the underlying discharge records and checked that the sub-totals reconcile to the published total.The assurer will test whether the category analysis is mathematically sound, whether categories overlap, and whether the same discharge has been counted more than once.['Category schedule with each line item assigned once only', 'Arithmetic check showing sub-totals equal the overall amount', 'Source data extract supporting the category split', 'Independent review or second-person check evidence']
For the water-stressed locations, I used the same reporting rules as for the wider dataset, but filtered the records to the relevant areas before calculating the amount.The assurer will examine whether the stress-screening was applied correctly, whether the location list is current, and whether the filtered amount is complete for those areas.['List or map of locations treated as water-stressed', 'Method note showing how the stressed-area filter was applied', 'Underlying records tagged to those locations', 'Reconciliation of the stressed-area amount to the filtered source data']

Evidence pack to prepare

Common reporting gaps

Figures are stated without the supporting narrative, or narrative without figures.Scope is inconsistent between the text and the numbers.The reporting boundary is left undefined.Material changes since the previous period are not disclosed.Estimates and measured values are not distinguished.Source records for the figures are not identified.
Common gaps

Mistakes to avoid when collecting the data

Wrong owner, wrong desk
People often ask the sustainability team for figures that sit with site operations, utilities, or the lab, so the first request goes to the wrong person and the source record is never found.
Using framework language instead of site terms
The data request is written in disclosure language rather than the organisation’s own process terms, so local teams cannot match it to the logs, permits, or spreadsheets they actually keep.
No clear boundary for what is in scope
Collectors fail to pin down which sites, outlets, or discharge routes are included, so some records are left out while others are counted twice.
Wrong reporting period or cut-off
The team pulls numbers from a different date range than the one used for the report, so late entries, corrections, or partial-period records distort the final set.
Mixing unlike counting bases
Volumes from different measurement methods are added together without checking the basis behind each source, which makes the combined total unreliable.
Losing the original source labels
Once the figures are copied into a working file, the site name, outlet code, or treatment route is stripped away, making it impossible to trace each number back to its origin.
Combining populations that should stay separate
Records for ordinary discharge, water sent on to another organisation, and water from stressed locations are merged into one pool, so the required splits cannot be rebuilt later.
Missing evidence trail and sign-off
The team keeps the numbers but not the supporting files, version history, or reviewer approval, so no one can show how the data was assembled or who checked it before submission.

Where judgement is often needed

Set the reporting perimeter after buy-ins and sell-offs
Explain which sites and volumes are kept in the year’s figures when ownership changes part-way through the period, and state the cut-off rule you used so readers can see why some flows were included or left out.
Reconcile local discharge labels across countries
Where site records use different national terms or permit categories, map them into one internal grouping and disclose the mapping so like-for-like totals can be understood.
Decide how to handle borderline sites and shared operations
State whether facilities just inside or just outside your operating control, joint arrangements, or leased premises were counted, and describe the rule used for those edge cases.
Choose the timing basis for the annual total
If some locations report by calendar month, permit cycle, or meter-read date rather than the reporting year, explain the timing basis and any adjustments made to align the figures.
Separate direct readings from calculated estimates
Disclose which volumes came from meters and which were estimated or modelled, together with the method used for estimates and any material gaps or assumptions.
Round consistently and show the effect on totals
State the rounding convention used for site and group figures, and make clear if small differences arise because rounded line items do not exactly add up to the published total.
Aggregate sensitive site data without losing meaning
If individual locations cannot be named or split out for privacy, security, or contractual reasons, explain the level of aggregation used and how readers can still understand the main pattern.
Explain how treated releases and third-party transfers were classified
Clarify whether treated outflows and any water passed to another organisation for its own use were counted in the main discharge figures or shown separately, and describe the basis for that choice.
Examples

Illustrative examples

Synthetic, written by LRA — not from a company report, not text from any standard.

Illustrative (synthetic) example — Food processing

Synthetic example only: we report where our water leaves the site, split by destination and by whether it goes to stressed catchments, and we note the small volume we pass on to another organisation for its own use. We also explain which priority pollutants we treat, how we defined that list, the limit-setting basis, any breaches, and the data boundaries used.

This example shows a concise way to present discharge volumes, stressed-area splits, third-party transfers, treatment scope for priority pollutants, limit-setting approach, non-compliance count, and the main compilation assumptions.

Illustrative water discharge summary (m3)
Rivers and streams420000180000
Public sewer9000030000
Coastal waters500000
Other destinations2000010000
Illustrative (synthetic) example — Chemicals

Synthetic example only: we present the same water-outflow picture for a different type of business, including the share sent to stressed catchments and the small amount transferred to other users. We also state the pollutants covered by treatment, the rule set used to define them, the discharge-limit method, any breaches, and the scope and estimation basis behind the figures.

This example demonstrates a second plausible reporting style with the same required content, using a different sector and a different mix of destinations and stressed-area volumes.

Illustrative water discharge summary (m3)
Surface water260000140000
Municipal sewer7000020000
Ground infiltration3000010000
Third-party transfer for use150005000
Company reports

How companies report GRI 303-4

Real reports where this topic is disclosed. These are report practice, not exact disclosure templates to copy.

ASE Technology Holding Co., Ltd.
Semiconductors · Taiwan · 2024
Open report →
ASE Technology Holding Co., Ltd.'s 2024 CSR Report provides numeric data on total water withdrawal and consumption, with specific values reported on pages 244 and 266, including water withdrawal in areas of water stress (p.244) and total water withdrawn (p.266). The report also includes figures on water recycling and reuse rates and mentions internal water quality testing (p.241, p.140). However, narrative explanations, methodologies, and certain detailed disclosures related to water management are either missing or unclear throughout the report.
MOEVE, S.A.
Oil and Gas · Spain · 2025
Open report →
Moeve, S.A.'s 2025 Consolidated Management Report provides numeric data on freshwater withdrawal in water-stressed areas over the past five years, showing values ranging from 12,506 to 14,723 thousand m3 (p.60). The report also includes figures on water use in stressed areas and overall water consumption (p.110). However, there is no narrative explanation or methodology provided regarding water withdrawal or management practices, and several expected narrative disclosures are missing or unclear.
Bangchak Corporation Public Company Limited
Oil and Gas · Thailand · 2025
Open report →
Bangchak Corporation Public Company Limited’s Integrated Sustainability Report 2025 provides numeric data on total water withdrawal and total water consumption for the years 2022 to 2025, with specific figures presented on pages 159 and 161. Additional numeric details on freshwater quality, measured by total dissolved solids, are included on pages 188 and 190, showing zero values across the reported years. However, the report lacks narrative explanations or methodological details related to water management, as no quotable narrative evidence was found.
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Scenarios to work through

A manufacturing site sends 1,200 m3 of treated process water to a municipal sewer, 300 m3 to a river, and 100 m3 to a third party for reuse. The reporting team has separate logs for each outlet, but the draft only shows the combined figure.

QHow should the team present the discharge figures so the reader can see both the overall amount and where it went?
Reveal model answer →

A site in a water-stressed basin discharged 450 m3 during the year, including 120 m3 to a nearby industrial user and 330 m3 to a treatment works. The preparer is unsure whether the stressed-basin amount needs its own breakdown.

QWhat should be done with the water-stressed discharge data?
Reveal model answer →

A food processor treats wastewater before release and removes metals and cleaning chemicals above internal thresholds. The draft report says only that the water was treated, without explaining which substances were targeted or how the limits were set.

QWhat extra detail is needed about the treatment of substances of concern and the limits applied?
Reveal model answer →

A plant had two exceedances of its discharge limits during the year: one for a cooling-water outlet and one for a wastewater line. The draft includes the count, but no note on how the figures were compiled or whether any third-party water was passed on for use.

QWhat should the preparer add so the disclosure is understandable and complete?
Reveal model answer →
Framework references

Related framework references

How this disclosure maps across the major reporting frameworks.

GRI
GRI 303-4
within GRI 303: Water and Effluents
Open official source →
Primary
Related & explore
FAQ

Questions this page answers

What do I need to gather before drafting GRI 303-4 Water and Effluents on this page?+
How do I decide the scope for GRI 303-4 Water and Effluents using this guidance page?+
Which data owner should provide the discharge by destination and third-party water transfer figures for GRI 303-4?+
What evidence should I keep to make a GRI 303-4 Water and Effluents disclosure assurance-ready?+
How do I use the Prep & Assurance workbook for GRI 303-4 Water and Effluents?+
What are the common mistakes to avoid when reporting GRI 303-4 Water and Effluents?+
Can I use the synthetic example on the GRI 303-4 Water and Effluents page as a template for my own disclosure?+
What should the narrative section of a GRI 303-4 Water and Effluents draft include?+
How do I write the GRI content-index line for the Water and Effluents disclosure from this page?+
How does the ESRS E3 Water and Marine Resources reference help me with GRI 303-4 Water and Effluents?+
More questions this page can help with
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