Farmers have been paying less for water since 2000 but household bills have gone up, according to researchers at Groningen Univeresity.

The country’s 24 water boards, which are responsible for dyke safety, water purification and environmental protection, cost €2.5bn a year, the researchers, quoted by tv show Nieuwsuur, say.

But since 2000, there has been a shift in the way the bills are paid. Households are now paying an extra €650m a year towards the water boards but farmers’ bills have gone down by €65m.

The €1.3bn annual cost of managing the water supply system has shifted from a 70:30 payment ratio to 90:10.

The water companies themselves say households are paying more because the boards have been given more jobs ‘to guarantee dry feet and ensure balanced water ecology’.