Water Availability Regulations at a Glance: Adopted Water Availability Regulations


Exemption for residential subdivisions of 5 or fewer lots if:

  1. lot size averages at least 2 acres; and
  2. uses surface water, or:
  3. if uses groundwater, each lot has only one well, each lot has a 2500 gallon rainwater harvesting system, export of groundwater outside subdivision is prohibited, and further division of lots is prohibited for five years.

Exemption from groundwater availability certification requirement for subdivisions supplied by Manville Water Supply Corporation.

Exemption if a completed preliminary plan or final plat application was filed before the date of this regulation (unless land is further subdivided to create more lots/parcels/units of development).


All subdivisions must have a plan showing adequate water and wastewater, including description of new or existing facilities, sources of water, etc.

Residential subdivisions of 15 or more units must also include plan for drought or other water shortage, detailing emergency response stages, targets for water use reductions, etc.

Supplemental Information for Groundwater Availability Certification

Supplemental information is required within 1000 feet of the subdivision boundary.

Applicant must mail a written questionnaire to adjacent land owners.

Monitoring Requirements for Subdivisions Using Groundwater

Residential subdivisions of 15 or more units and commercial subdivisions using over 100,000 gallons per month required only to install monitoring equipment.

County will be responsible for monitoring.

Common Area Features

Groundwater can be used for common area features, including amenity ponds, landscaping, and sports fields, subject to the following:

  1. If there is a centralized wastewater system, groundwater may only be used until treated effluent is available.
  2. Volume of ponds and water features using groundwater may not exceed 2 acre feet individually and 6 acre feet cumulatively.
  3. Use of groundwater for common areas must be accounted for in groundwater availability certification and must be curtailed in first stage of drought.

Fire Protection

Fire protection required only for:

  1. Residential subdivisions of 15 or more units supplied by a centralized water system, and
  2. All commercial subdivisions.

Colorado River Alluvial Aquifer

May not be used as a source of water supply in new subdivisions.

Development Intensity Affecting Trinity and Edwards Aquifer Groundwater

Commercial over Trinity and Edwards aquifers:

No impervious cover limit if (1) primary driveway access is on a state road, or (2) meets Alternate Standards in Highland Lakes provisions of County Code. Otherwise, 45% impervious cover limit.

Residential over Trinity and Edwards aquifers:

No impervious cover limit if (1) average lot size is at least 1 acre, or (2) conservation area requirements of the County's Conservation Subdivision Ordinance are met. Otherwise, 30% impervious cover limit.

If using groundwater water from Trinity or Edwards aquifers, minimum lots size of:

  1. 5 five acres for subdivisions with individual wells on each lot; and
  2. 3 acres for subdivisions supplied by centralized system, or the total number of lots shall not exceed the number of acres in the subdivision divided by four.

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