New figures show that complaints from customers to South West Water (SWW) more than doubled in the last year, the sharpest rise of any water and sewerage company in the country. Across all water companies, household complaints rose by 56% in 2025-26, while SWW saw a 153% surge.
The consumer watchdog rated both SWW and Thames Water as "poor" for the number of complaints they received and how they handled them. SWW said it was "taking action" to improve and "knows there is more to do to improve our customers' experience".
The Consumer Council for Water (CCW) said SWW had the sharpest rise, though it came second to Thames Water for complaints per 10,000 connections in 2025-26. The watchdog, an independent body representing consumers in the industry, assesses each company on two measures: complaints per 10,000 households served, and the effort customers must put in to get a complaint resolved. Both SWW and Thames Water were rated "poor" on both measures, making them the worst performing companies.
Catherine Jones of the CCW said: "This is the second successive year SWW has found itself among the worst performers for complaints." Citing "significant bill rises" over the past two years, she said customers "need to see their money is being well spent and making a difference where they live – whether that's cleaner seas and rivers or getting the support they need when they are struggling to pay their bill."
In 2025-26, SWW received 18,938 complaints, or 183 per 10,000 connected households. That was up from 7,485 the previous year. Billing issues were the main source of complaints in 2025-26, making up 76% of the total. Water accounted for 17% and wastewater for 6%.
Complaints about SWW escalated to the consumer watchdog after going through company procedures also more than doubled, from 284 in 2024-25 to 716 in 2025-26. Southern Water had the sharpest rise in watchdog complaints in this category, up 166%, followed by SWW and then Anglian Water.
Concerns and confusion over rising water bills again fuelled the largest-ever increase in complaints about water companies to the watchdog. The overall number of complaints made directly by households to their water company rose to 321,347 in 2025-26, up from 205,853 in 2024-25.
This comes after water companies were allowed to increase customer bills by an extra £3.4bn in coming years to meet increased pressures on infrastructure and the environment. Portsmouth Water and Bristol Water were the only companies rated "good".
South West Water Reports Sharpest Rise in Complaints