Water Regulation Improvement Act of 1999

Water Regulation Improvement Act of 1999 - Amends the Federal Water Pollution Control Act to require permits for discharges from municipal storm sewers to: (1) recognize the responsibility of governmental entities to carry out specified control measures to reduce the discharge of pollutants; and (2) absolve local governmental entities of liability in cases where such an entity relies on a co-permittee or another governmental entity to comply with any requirement to implement a control measure in which the co-permittee or other entity assumes responsibility but fails to implement the measure.

Prohibits the Administrator of the Environmental Protection Agency, for certain stormwater discharges for which permits are not required, from requiring a local governmental entity to obtain a permit for any stormwater discharge associated with an above-ground vegetated drainage ditch or a drainage way owned or operated in connection with a road or street under its jurisdiction. Provides that such discharges and those regulated as being associated with industrial activity or with significant violation of a water quality standard or significant contributions of pollutants shall not include stormwater discharges associated with: (1) a construction activity that disturbs no more than five acres of land; or (2) a routine maintenance activity associated with a road, street, or vegetated road ditch or drainage way.