Water and sewage service provider Severn Trent's pretax profit fell as the company tries to keep in line with regulations and maintain low prices for consumers.
Pretax profit dropped by 53.5% to £148.2m.
Severn Trent said it had "made good progress on a number of Ofwat's [the regulator] key performance indicators (KPIs), including a 20% decline in internal sewer flooding incidents, pollution incidents down by 18%, a 4% reduction in greenhouse gas emissions and a 38% reduction in supply interruptions greater than three hours," it said in a statement.
"We have had at, or below, inflation increases in our customer bills for six consecutive years, and Severn Trent Water's customers continue to benefit from the lowest average combined water and sewerage bills in Britain."
Chief executive Liv Garfield said: "Our focus remains on the customer and with average bills falling year on year and the lowest average bills in Britain until at least 2020, our customers are receiving good value for money.
"Our performance over the last year has also demonstrated where we are strong and the areas we need to focus on to drive improvement. Water quality remains a key focus area for us. We have hit our target of a 10% reduction in leakage over AMP5 and improved our customer service performance, creating 100 new front line roles in the process."