1-01-07 A new water improvement tax for the city of Ardmore takes effect Monday. Voters approved the new water tax in July 2006. Officials say the tax will be used to fund water and wastewater improvements. According to authorities the tax will raise the city's sales tax half of one percent. The city of Ardmore says the tax will only cause a slight increase in water and wastewater services. Officials say the tax should be in effect for five years.