First in time, first in right
Colorado’s climate is mostly dry and sunny. It is commonly known as a semi-arid state, making water and the right to tap into it a precious commodity. In Colorado, water rights play a significant role in  securing enough water to sustain a community.

Tributary water is regulated by the Prior Appropriation Doctrine, which means that municipalities who filed for a water right first have the most senior rights. All those after have junior rights and may not take water from the river until all the senior water rights have been satisfied.

Castle Rock owns several hundred acre-feet of senior tributary (renewable) water rights on East and West Plum Creek, from down near Larkspur all the way north to Sedalia. These water rights can be used from April to October when in priority.

• The availability of the water rights depends on the hydrologic cycle. For example, if it is a hot, dry summer, most likely all the senior water rights will “call” all of the water in the creek. None will be left for junior water rights holders. Conversely, on a cool, wet summer, most likely all of the water rights – senior and junior and then some – will be available to take out of the creek.
• These water rights can be taken from different parts of the creek according to court decrees, as long as taking the water will not injure or harm someone else’s water right.

Castle Rock owns tens of thousands of acre-feet of groundwater beneath the Town.

• These water rights can be used year-round and are not subject to the hydrologic cycle, which makes groundwater an excellent water supply during droughts.
• These water rights are attached to parcels of land. Meaning, when you sell your plot of land, most likely there is groundwater underneath the property that is sold with that parcel.

Securing Castle Rock’s water supply is our first priority today and in the future. Currently, Castle Rock’s water demands are met with 100 percent groundwater. When the Town is fully built out, it is planned that the water demand will be met by 75 percent renewable water and 25 percent nonrenewable water.

We own water rights that date back to the 1860s and we work hard to protect and maintain those individual water rights. Part of our long-term water strategy is to start tapping into more of these rights, to enhance our current water supply. Our goal is to ensure adequate water resources, for all Castle Rock residents and business owners, well into the future.