Pitkin County, Colorado

(Profiled 2-19-21)

Pitkin County, Colorado, population 17,767 (2019), surrounds the affluent ski resort of Aspen in the mountainous center of the state. To keep growth from degrading environmental resources, the county aims to steer higher-density development into the Urban Growth Boundary (UGB) and allow mostly lower-density residential, agriculture/ranching, and open space outside the UGB. The county also anticipates that climate change will cause wildfires to continue increasing in size, intensity, and frequency over time. To reduce human exposure to fire and other disasters, the county’s Hazard Mitigation Plan recognizes that the TDR program works with UGB policy by motivating the redirection of growth from hazard-prone areas and rural zones into places more suitable for development where it can benefit from infrastructure, emergency services, and public services.

In 1996, the Pitkin County Board created the county’s Rural/Remote (R/R) zoning district to limit growth in backcountry areas which are characterized by sparse development, little or no access to traditional county emergency services, absence of utility districts, and exposure to natural hazards. This zone requires a minimum lot size of 35 acres and cabins here cannot exceed 1,000 square feet of floor area. Alternatively, owners of property in the R/R can choose to record covenants permanently precluding further development in return for one TDR per each full 35 acres or legally-created parcel smaller than 35 acres. Concurrent with the recording of the covenant, the county issues an irrevocable certificate of development rights. Within five days of the sale, assignment, conveyance or other transfer or change of ownership of a TDR certificate, the county must be notified of the certificate number, the grantor, the grantee, and the total value of the consideration paid for the certificate.  

Since then, Pitkin County expanded opportunities for owners to participate by adding sending area potential for various forms of preservation in other rural districts including environmentally-sensitive properties and land with environmental hazards including geologic instability, steep slopes, and vulnerability to wildfire.

As of January 2021, sending sites include the following:

  • Legal lots and parcels zoned R/R or Transitional Residential (TR-1 and TR-2);
  • Land zoned Conservation Development PUD (CD-PUD); 
  • Constrained or visually-constrained land not zoned R/R, CD-PUD, TR-1 or TR-2;
  • Limited Development Conservation Parcels zoned AR-10, RS-20, RS-30, RS-35 or RS-160; and
  • Properties designated in the Pitkin County Historic Register.

As of January 2021, the following allocation ratios apply:

  • The allocation ratio in the TR-1 is the same as in the R/R: one TDR per 35 full acres or legal lot larger than one acre but smaller than 35 acres. Under the conditions described below, a legal lot zoned R/R or TR-1 that is smaller than one acre may also qualify for one TDR;  
  • In the TR-2 zone, the code allows one TDR per ten full acres or legal lot larger than one acre but smaller than ten acres. Under some circumstances a legal lot zoned TR-2 (as well as R/R and TR-1) that is smaller than one acre may qualify for one TDR by proving that the site has legal access and can accommodate a well, on-site wastewater treatment and a 1,000 square foot building pad; 
  • At a public hearing, the Board of County Commissioners (BOCC) may issue one or more TDRs to constrained sites or one TDR to visually-constrained sites;
  • For sites zoned CD-PUD, one TDR can be issued for each 35 acres preserved and excluding the 160 acres designated for development);
  • On a Limited Development Conservation Parcel, one TDR can be issued for each 35 acres preserved after deducting 35 acres for each legal dwelling on a parcel less than 640 acres and deducting 70 acres for each legal dwelling on properties with 640 acres or more; and
  • The BOCC may approve the granting of TDRs to properties designated in the Pitkin County Historic Register.

The Pitkin County TDR program motivates owners of qualified sending sites to participate with sale prices that ranged from $115,000 to $318,000 per TDR between 2007 and 2019. In 2019, ten TDRs sold at prices ranging between $225,000 and $240,000 each (Condon 2020). 

TDRs cannot be received on land zoned R/R, RS-160, TR-1, RS-G, MHP, AH, AH-PUD, B-1, B-2, VC, P-I, T, SKI-REC, VR, I, PUD, AC-REC-2 or FPV-O. 

In receiving areas, property owners can use TDRs from any sending site to obtain an exemption for a new development right in the Aspen UGB under the Growth Management Quota System (GMQS). The GMQS uses a point system to score proposed developments based on how well they meet desired criteria. A proposed development that scores high may receive a permit to build a residential unit and/or gain bonus floor area within an individual dwelling unit through the GMQS annual quota without having to buy TDRs. However, a low-scoring project may have to wait year after year unless the developer uses the TDR option. The number of TDRs required for exemptions from GMQS varies depending on the size of the proposed residence. Transfers used to receive an exemption to build a new residential unit are approved by a One-Step Special Review of the BOCC.

TDRs from any sending site can also be used to exceed a baseline floor area of 5,750 square feet on receiving sites in the Aspen UGB and approved subdivisions up to the final maximum floor area allowed within each individual home. For receiving sites zoned TR-2, each TDR yields 1,000 square feet of additional floor area. On receiving sites in other zones, the ratio is 2,500 additional square feet of floor area per TDR. These transfers are approved by a One-Step Special Review conducted by the Hearing Officer.

As of 2020, the county had issued certificates for 389 TDRs and 254 TDRs had been transferred to receiving sites, with 82 percent of these TDRs used to exceed the baseline floor area of 5,750 square feet. At that time, TDRs had preserved a total of 8,879 acres. 

In October 2020, county staff estimated that 20 years would be needed to absorb the remaining 135 TDRs unless the program was modified. At that time, staff was considering various ways of dealing with the possibility of TDR oversupply, including the cessation of issuing new TDRs. However, a real estate agent who assists with TDR transactions argued that the county should not stop issuing new TDRs because the apparent oversupply of existing TDRs was misleading. The agent estimated that 12 TDRs had been sold in the prior year and that he was having difficulty finding the ten TDRs wanted at receiving sites because many of the 135 unextinguished TDRs were “locked up” and could not be used in the near term for various reasons. As of October 2020, staff planned to expand public outreach as part its review of all county growth management tools including TDR (Condon 2020). 


Condon, S. 2020. Transferable development rights under scrutiny as Pitkin County sharpens growth management tools. Aspen Times: 10-10-20. Accessed 2-19-21 at Transferable development rights under scrutiny as Pitkin County sharpens growth management tools | AspenTimes.com.