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Transferable Development Rights (TDR) FAQs

The Boulder County Community Planning & Permitting office at 2045 13th St., Boulder is open to the public on Monday, Wednesday, and Thursday from 8 a.m. to 3 p.m., and on Tuesday from 10 a.m. to 3 p.m. Appointments are available on Tuesday but are not required. Schedule an appointment.

Transferable Development Rights (TDR) FAQs

Find answers to frequently asked questions below:

Where can I find out who has TDRs they want to sell?

In Boulder County, check with the Community Planning & Permitting Department or realtors. We are considering setting up an information clearinghouse or TDR repository that people could access to answer this and the next question.

Where can I find out if someone is interested in buying my TDRs?

In Boulder County, check with the Community Planning & Permitting Department or realtors. We are considering setting up an information clearinghouse or TDR repository that people could access to answer this and the next question.

If I purchase TDRs, am I the only one who can use them or can I sell them to someone?

TDRs can be bought and sold over and over, but each transaction requires the issuance of new TDR certificates and recordation with the Clerk and Recorder. TDRs cannot be used on other sending sites that have had their TDRs purchased, nor can they be used on the property from which they were purchased.

How long is a purchased, but unused TDR good for?

Under the regulations which have been adopted, an unused TDR does not expire. This relates to the concept of “banking” discussed earlier.

Can local governments buy TDRs and bank them for resale to developers?

Yes. This is not a priority element of Boulder County’s program, but the Land Use Code does permit government involvement. One of the primary reasons for government involvement is to provide some assurance to receiving site developers that purchasable units are available at a realistic price. Through the purchase and sale of TDRs, a local government could obtain funds to purchase additional open space land. Government participation in the buying and selling of TDRs is common to several programs in the United States.

Why aren’t the sites mapped?

While mapping potential receiving areas provides a certain amount of assurance to property owners as to the status of their land, it could also artificially raise or lower property values based on speculation. By not mapping receiving sites, property owners are given flexibility to propose their land as a receiving site and show how it meets the criteria for approval. When a receiving site is proposed, neighboring property owners are notified and public hearings are held. Through these steps, the community becomes involved in the decision-making process.

Is there a limit on the size of a receiving site?

While there is no set acreage for a receiving site (called a TDR Planned Unit Development), the maximum total number of units placed on one site is 200. It is very likely, however, that most proposed sites will be more suitable for considerably fewer than 200 units because of neighborhood compatibility issues and infrastructure demands.

Can development rights be transferred from anywhere in the county to a receiving site?

In general, 75% of the units transferred to a receiving site must come from the sub-area surrounding the site. When the county has entered into an intergovernmental agreement with a city or town, the terms of the agreement will apply. For example, a city could require all TDRs come from within its planning area instead of the 75% requirement. Exceptions to the 75% could be made if approved by the Board of County Commissioners.

Why won’t TDR units serve as affordable housing?

Receiving sites will typically be low to very low density with large lots, one-half acre or more in size.
The fewer the lots that a developer plats on a site, the more he or she needs to charge to get the same return on the initial investment. People buying larger, more expensive lots are more likely to want larger, more expensive homes. In some cases, their lenders may require that the home be more expensive in order to maintain a ratio between the cost of the land and the cost of the improvements (home). In addition to the cost of the land itself, the cost of the purchased TDR units must be calculated. It is estimated that between $20,000 and $50,000 could be added to the cost of each TDR lot.

Could TDR units be part of an affordable housing program?

Yes. If a municipality participating in the TDR program wished to add an affordable housing element to a receiving site, it could be feasible to lower the overall price of the housing units on the site.
This could be accomplished in several ways. The most likely way would be for the city to allow increased density on the receiving site. The more lots on the site, the less the developer has to charge for each one in order to get the same return on the initial investment. The involved city or town could allow multifamily residences and small lot single-family residences, mixed together with the larger TDR lots to create a more diverse and affordable neighborhood. Of course, higher density affordable housing translates into more demand on schools, transportation routes, and other infrastructure. A second option to add an affordability element would be government subsidy of the TDR lots.

Can single-family residence TDRs be converted into “x” square feet of commercial or multi-family space? For example, could one TDR unit be equal to “x” square feet of retail space?

Not as of yet in Boulder County. Conversion formulas do exist in other programs around the United States, usually in municipal or urbanized areas.

Do the Non-Urban Planned Unit Development (NUPUD) and Transferable Development Rights (TDR) Programs depend on each other?

NUPUDs can and have been approved without the TDR program since 1978. In turn, the TDR program does not depend on the NUPUD program. Both programs are voluntary and both are techniques for a property owner to gain some bonus density for a piece of land while preserving identified natural resources.

How do NUPUDs and TDRs differ?

The main difference between a NUPUD and a TDR is the location of the development that results from the bonus density.

NUPUD development occurs on the property itself. TDR development, on the other hand, requires that the development rights be sent from the original property to an entirely difference piece of land (the receiving site).

I’ve heard that you can’t build a house in Boulder County unless you have 320 acres. Is this true?

No, it is not true. Neither the NUPUD or the TDR programs change the fact that 35 acres is the minimum lot size in most Boulder County zoning districts. The 320 acre minimum refers to the amount of land needed to apply for an NUPUD, in most cases.

I have 140 acres. Can I apply for an NUPUD?

Although the minimum acreage needed to apply for an NUPUD is now 320 acres, there are exceptions to this rule. The exceptions are based primarily on the contiguity of the proposed NUPUD to existing development. No matter what the size of the property, at least 75% of the parcel must have natural or cultural resource designations as mapped in the Boulder County Comprehensive Plan. If you have specific questions about whether your property would qualify, you should contact the Community Planning & Permitting Department at 303-441-3930.

For complete information about the regulatory issues related to TDRs, consult the Boulder County Land Use Code Article 6.

Contact Us

Community Planning & Permitting (formerly the Land Use Dept.)

Email: Ask a Planner Form
Main: 303-441-3930

Courthouse Annex Building

2045 13th St.
Boulder, CO 80302


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10 a.m. to 3 p.m. Tuesday
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Community Planning & Permitting
PO Box 471
Boulder, CO 80306
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