• Know your soil
• Water sparingly and at the right time of day
• Use fertilizer properly
• Apply mulch
• Plant more perennials
• Start a compost
• Take care of your lawn in the fall before winter
• Make sure you aren't cutting your grass too short

Here are some additional resources on protecting clean water:

Live Green Twin Cities - Top 10 tips for saving water this summer

Natural Resources Conservation Service - Lawn and Garden Care

Minnesota Department of Agriculture - Lawn Care and Water Quality

University of Minnesota Extension - Garden