The new annual charges, collected alongside local authority council tax, will mean an average bill increase of 31 pence per week. Around half of households in Scotland receive financial support as they automatically have either a discount, exemption or reduction applied to their water and wastewater charges.

Scottish Water serves 2.6 million households supplying 1.5 billion litres of water and removing and cleaning 1 billion litres of used and surface water daily.

Water and waste water charges, which raise almost £1 billion annually, supports service delivery, investment in ageing infrastructure and improvements in water quality and environmental protection.

Scottish Water said it needs to increase investment to protect services against the impact of climate change, reduce carbon emissions and ensure customers have reliable and resilient services in future.

Douglas Millican, chief executive of Scottish Water, said: “Customers rely on our services for their daily water needs and to take away and clean the water they use. Over the last two years those services have been vital to maintaining public health during the pandemic.

“We have been recognised as leading in the water sector in the UK on customer service excellence, the quality of Scotland’s drinking water remains very high, and we are investing to protect the environment from pollution.

“Higher levels of investment are needed to protect services now and over the long term, particularly in meeting the challenges of more intense rainfall, flooding, and drought, and reducing carbon emissions.

“We understand there needs to be a balance between the need for higher levels of investment and the financial challenges faced by households at the present time. We have set charges at a level that takes account of those challenges while being open and clear that charges will need to increase further in future years.”

Water and waste water charges to licensed providers who supply businesses and other non-domestic customers will also increase by 4.2%.

Unmetered Household charges 2022/23

Net zero and energy secretary Michael Matheson said: “We remain committed to supporting people facing issues paying their water bills. While UK-wide energy prices rise beyond inflation, in Scotland the increase to water charges for 2022-23 has been set at 4.2% - in line with inflation.

“In developing the charging principles for the industry for 2021-27, Ministers took the decision to increase the levels of support for those vulnerable customers who have the most difficulty paying. The water charges reduction scheme discount has increased from 25% to 35% - protecting thousands of eligible households from higher charges.

“Households in receipt of the full water charges reduction scheme discount will actually pay less than they did in 2020-21.

“In addition, water charges in Scotland remain linked to council tax bands - which means that discounts which apply to Council Tax, such as the single person discount, also apply to water and sewerage charges.

“Keeping our water services in public ownership means that every pound raised is re-invested in our water industry. Our average water charges remain lower than the average in other parts of the UK - in 2021-22 the average charge in Scotland is £375, compared to £408 in England and Wales.”