The regulator completed over 10,000 checks across England in the past year, a record number, including more than 730 inspections of Southern Water’s wastewater sites across the South.
While 68 per cent of the company’s sites were found to be compliant with environmental permits, inspectors uncovered a series of problems ranging from poor maintenance to serious gaps in operational knowledge.
In several cases, operators were reportedly unsure where their discharge points were located, or these were found to be inaccessible.
General maintenance also emerged as a major concern, with faulty screening and storm tank mismanagement among the most common shortcomings.
The agency said these findings show that more work is needed to bring Southern Water’s operations in line with environmental regulations designed to prevent pollution and protect local watercourses.
Dawn Theaker, water industry regulation manager for the Environment Agency, said: “Environment Agency inspectors are working very hard visiting hundreds of sites, each a key part of the water and sewage systems everyone relies upon.
“These health checks find issues Southern Water needs to fix because if things go wrong, the environment suffers. We will keep returning until faults are fixed.”
The inspections are part of a wider national effort to clamp down on poor performance in the water industry. The Environment Agency has strengthened its enforcement capacity, introduced better data systems, and given inspectors greater powers to demand change.
Helen Wakeham, the agency’s director for water, said the focus is on preventing pollution before it happens. She said: “Inspections are a vital preventative measure.
“Together, this work will drive improvements in performance, hold persistent offenders to account, and create a cleaner water environment.”
Although some of the permit breaches were relatively minor, the agency said they still point to deeper issues around maintenance and environmental management. More serious breaches could face further investigation or even prosecution.
The Environment Agency said the information gathered from these inspections is being used to strengthen regulation and target recurring problems.
Southern Water is among several companies expected to benefit from a £22.1 billion investment package agreed with regulators to upgrade ageing sewage infrastructure over the next five years.
A Southern Water spokesperson said: “We continue to be open and transparent, and work closely with the Environment Agency and local stakeholders, including MPs, to meet the standards our customers and communities expect. That includes taking action whenever issues are identified.
“Pollution incidents have fallen by 30% since 2023, reflecting the real progress we’re making on environmental performance. We’re investing more than £8.5 billion between 2025 and 2030 to upgrade infrastructure for customers and to protect the environment.”
They added that since their turnaround plan launched in April 2023, “real change” was delivered by Spring of 2025 and that the vast majority of the 400 required actions relate to “relatively minor breaches.”
They stated that alongside the number of pollution incidents falling by 30%, internal sewer flooding fallen by 40%, drinking water quality compliance rose by 40% and leakage was reduced last year by a record 18.5%.
