How does the environment agency assess Discharges to surface water and groundwater: assessing environmental permit compliance

In England, the Environment Agency (EA) assesses discharges to surface water and groundwater by considering whether an activity complies with its environmental permit and whether the discharge presents an unacceptable risk to the environment.

The assessment considers the quality and quantity of the discharge, the sensitivity of the receiving environment, the effectiveness of treatment, monitoring results and compliance with permit conditions.

For contractors, wastewater treatment operators and businesses discharging process water, this means that having a treatment system in place is not enough: the discharge must meet the requirements of the relevant permit.

In Wales, the equivalent environmental regulator is Natural Resources Wales (NRW), so the applicable regulator and guidance depend on where the discharge takes place.

The main official document is the Environment Agency's Discharges to surface water and groundwater: assessing environmental permit compliance, updated on 5 June 2026. It explains how the EA records breaches, assesses their potential environmental impact, identifies root causes and determines the risk category of non-compliance.

1. What does the Environment Agency assess?

The EA uses a case-by-case approach based on the permit, the activity and the potential consequences of a breach.

These areas reflect the EA's compliance assessment framework, including infrastructure, management, emissions, incident planning, monitoring, maintenance and reporting.

2. How does the EA determine the seriousness of a breach?

The EA considers the reasonably foreseeable impact of a non-compliance: in other words, the potential consequences if the problem is not addressed promptly and adequately.

It assigns one of four risk categories.

The category is not determined solely by the numerical size of the breach. Location, the type of pollutant, the duration of the failure and the sensitivity of the receiving environment all matter. The EA also considers the pollution controls available and how effectively the operator responds.

For example, the same discharge-control failure could present a greater risk where a drinking-water abstraction or sensitive habitat is nearby than at a less sensitive location.

3. How does the EA carry out a compliance assessment?

The EA can use a combination of the following methods, depending on the activity and its risk.

• Site inspections: checking discharge points, treatment equipment, drainage, storage and pollution prevention measures.

• Sampling and analysis: collecting discharge samples or reviewing laboratory results against permit limits.

• Monitoring data reviews: checking flow rates, pollutant concentrations, records and any required environmental monitoring.

• Management audits: examining operating procedures, staff competence, maintenance, incident plans and reporting arrangements.

• Incident investigations: investigating pollution events, permit breaches and failures of pollution-control systems.

The EA records identified permit breaches through a Compliance Assessment Report (CAR). The report identifies the non-compliance, its risk category, corrective actions and any deadlines or potential enforcement action.

4. What happens when the EA identifies a breach?

The EA normally sends the CAR to the permit holder within 14 days of the assessment or receipt of the monitoring data being assessed. The report can still be issued when no non-compliances are found. Permit holders can raise concerns about the report within 14 calendar days of receiving it, followed by a request to appeal the regulatory decision within 28 calendar days of receiving the response, if the disagreement remains unresolved.

5. How does the assessment differ between surface water and groundwater?

The permit conditions and risk assessment must reflect the particular discharge and its receiving environment. For example, a groundwater assessment may need to establish how a pollutant could migrate through the soil and reach an aquifer. For surface water, the assessment may need to determine how the discharge affects the receiving river or other water body.

6. Example: a contractor discharging concrete wash water

Consider a construction site where concrete wash water is collected and treated before a proposed discharge to a nearby stream.

Scenario A: Treatment is operating as intended

• The contractor operates the permitted treatment system, maintains settlement tanks and pH controls where required, follows the permit's sampling and discharge conditions, and keeps records.

• Evidence of compliance

• The EA would consider whether the actual discharge and management arrangements satisfy the permit conditions.

Scenario B: High-pH water escapes into a stream

• A failed tank or uncontrolled drain allows alkaline wash water to escape. The EA would investigate the breach, consider the potential effects on aquatic life, examine the receiving water's sensitivity and assess the adequacy of the site's pollution controls.

• Potential permit non-compliance

• The risk category would depend on the evidence and reasonably foreseeable impact, not merely on the fact that an escape occurred.

This example is illustrative, not a determination of a particular site's compliance. Concrete wash water can be highly alkaline and may contain suspended cementitious solids and other contaminants. An environmental permit, where required, must authorise the proposed activity; treatment alone does not authorise a discharge.

7. Practical compliance checklist for operators

Use this checklist to prepare for an EA inspection or internal environmental audit.

The checklist is a practical preparation tool, not a substitute for checking the specific permit conditions.

Official guidance and next steps

• EA: Assessing environmental permit compliance for discharges

• EA: Environmental permits for discharges to surface water and groundwater

• EA: Surface water pollution risk assessment

• NRW: Guidance on applying for and complying with water discharge permits

One important distinction: the compliance-assessment document explains how the regulator assesses breaches of an existing permit. The environmental risk assessment guidance explains how the regulator assesses the risks of a proposed discharge when deciding whether and on what conditions to grant a permit.