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Do I need a trade effluent licence to discharge to sewer in Ireland?
Quick answer
Yes. Any business discharging trade effluent to a public sewer needs a licence, and discharging without one is an offence. Uisce Éireann issues licences under Section 16 of the Local Government (Water Pollution) Acts for activities below EPA thresholds. Sites with an EPA licence are controlled through that licence, with Uisce Éireann consulted on any sewer discharge. Most licences limit volume, pH, temperature, COD, suspended solids and fats, oils and grease, and require self-monitoring with results reported to Uisce Éireann.
Who issues the licence
What the licence controls
| Area | What is set in the licence |
|---|---|
| Quantity | Volume and flow rate, and the times you may discharge |
| Quality | pH, temperature, COD, suspended solids, fats, oils and grease, and ammonia, nitrogen or sulphates |
| Treatment | Pre-treatment required before the effluent reaches the sewer, and the discharge point |
| Monitoring | Self-monitoring, sampling and analysis, with results reported to Uisce Éireann |
| Records | Notifications, record keeping and reporting |
| Charges | Charges approved by the Commission for Regulation of Utilities (CRU) |
Why sewer discharges are getting more attention
Public wastewater plants are under pressure. In its October 2025 report, the EPA found that 59% of existing treatment plants failed to consistently meet their licence standards, and 14 large towns and cities failed EU standards. When a public plant is stretched, the strength and timing of what businesses send into the sewer matters more.
The EU's recast Urban Wastewater Treatment Directive (EU) 2024/3019 entered into force on 1 January 2025 and must be in Irish law by 31 July 2027. It adds nutrient removal, removal of micropollutants largely funded by the pharmaceutical and cosmetics industries through extended producer responsibility, energy neutrality for treatment plants by 2045, and health-related monitoring of wastewater.
How to stay inside your licence
- Keep a copy of your licence limits where operators can see them.
- Monitor pH and flow continuously where you can; they move fastest.
- Sample COD, suspended solids and FOG at the frequency your licence sets, and on time.
- Check every result against the limit, and note how close it is.
- Maintain pre-treatment such as grease traps, screens and pH correction on a schedule.
- Tell Uisce Éireann about changes in production, volumes or processes before they happen.
- Keep records ready for sampling and audit visits.
Questions plants ask
Who issues trade effluent licences in Ireland?
Uisce Éireann, under Section 16 of the Local Government (Water Pollution) Acts 1977 and 1990, for activities below EPA thresholds. EPA-licensed activities are controlled through the EPA licence, with Uisce Éireann consulted on sewer discharges.
What limits does a trade effluent licence usually set?
Most set limits on volume and flow, pH, temperature, COD, suspended solids, fats, oils and grease, and sometimes ammonia, nitrogen or sulphates.
Do I have to monitor my own discharge?
Most licences require self-monitoring, with results reported to Uisce Éireann. Uisce Éireann may also take its own samples and audit the site.
See what your own data says
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Book a free pilot by emailSources
- Uisce Éireann: About trade effluent
- EPA: Volume of raw sewage discharges halved, but many wastewater plants still poorly managed (October 2025)
- Matheson: Urban Wastewater Treatment Directive, Irish transposition (March 2026)
This guide is general information, not legal advice. Always follow your EPA licence and the EPA's current guidance.