DENVER -- Did Sunday night's snowfall make an impact on Colorado's drought? Water officials say we need three storms a week for the next six weeks just to get to normal winter snow levels.

COLORADO'S DROUGHT Water Restrictions By City Reducing Water Use RESOURCES State Drought Info Watering Schedule Adjusting Water Sprinklers Water Tips Gardening During Drought Drought Conditions U.S. Drought Monitor Western Water Supply Forecasts Colorado Reservoir Storage Status Colorado Snowpack Summary Drought FAQ

That means it could be a very tough summer and another year of strict water rules.

The Denver Post reported that some possible restrictions include limiting watering to twice a week, a total ban on watering if reservoirs don't reach 40 percent by July 1, limitations on commercial car washes, a complete ban on new home lawns, trees and shrubs, and new surcharges for water customers.

Water officials are expected to come up with a final plan by spring, depending on snowpack levels, but they say residents should prepare for the worst.

Denver and Aurora have announced the continuation of last summer's water restrictions, but both acknowledge the possibility of an all-out ban on outside watering.

Boulder's water restrictions will stay in place through at least April, when city officials will review the spring snowpack measurements.

Although Colorado's snowpack is ahead of last year's, it is only 73 percent of average. Denver received less than 9 inches of snow through Jan. 31, the lowest amount ever recorded.

Melting snow provides about 80 percent of the water in the state's rivers, lakes and reservoirs. The snowpack percentage is measured against a 30-year average.

"We would need about three storms a week like the one we had (Sunday) for the next five to six weeks to catch up to normal," said Denver Water spokeswoman Trina McGuire-Collier.

"The storm provided half of what we get in an average winter week," she added.

Denver's reservoirs are at about 45 percent of their capacity and dropping. Outside watering will be prohibited unless the reservoirs are at least 40 percent full by July 1.

The city also will consider a ban on new lawns and bans on planting of new trees, shrubs, annual beds or gardens in residential areas after May 3.

Aurora reservoirs are only 27 percent full. Spinney Reservoir only has about a 25-day water supply.