El Paso | ADUs and Duplexes

El Paso ADUs and Duplexes: Section 20.10.035, Lot Sizes and Parking

El Paso offers two ways to put a second home on a lot. An accessory dwelling unit adds a small home next to a house, under Section 20.10.035 of the El Paso Municipal Code. A duplex puts two homes in one building, in the districts the use table allows. This page sets out the rules for both, with the section for each. The El Paso overview gives the short version.

What El Paso Counts as an ADU

Section 20.02.029 defines an accessory dwelling unit as "an accessory building that is intended to be used as a dwelling unit." A dwelling unit, under Section 20.02.332, is separate living quarters with "its own permanently installed cooking and sanitary facilities." In plain words, an ADU is a full small home with a kitchen and a bathroom, on the same lot as a main house.

The Appendix A use table marks the ADU row with an "A," an accessory use allowed by right, in all 15 residential districts from R-1 to A-M. It is an "X" (not allowed) in the commercial and industrial districts, a "D" (detailed site development plan needed) in most special purpose districts, and a "P" in U-P, the Union Plaza District. The supplemental standards cell for the row cites "§ 20.010.10; § 20.010.20; § 20.010.35." The code has no sections with those numbers; the ADU rules are in Section 20.10.035, which the accessory buildings section also names.

Section 20.10.035 came from Ordinance No. 17532 of April 19, 2011 and was amended by Ordinance No. 18973 of September 3, 2019. It has two lists: subsection A for detached ADUs, which stand apart from the main house, and subsection B for attached ADUs, which share a wall with it.

Detached and Attached ADUs Side by Side

Source: El Paso Municipal Code, Sec. 20.10.035, Supplement 95 Update 4.

Both lists say the ADU "shall comply with all building code requirements for a dwelling unit, including but not limited to, heating and cooling, cooking and bathroom facilities," and both allow vehicle access "from an abutting alley if on-site parking is provided for the ADU." Gross floor area (gfa in the code) is the floor area measured to the outside of the walls.

The Detached ADU in Detail

Subsection A begins: "In addition to the regulations in Section 20.10.030, detached accessory dwelling units in residential zoning districts shall comply with the following." Its thirteen rules cover more than size:

• Owner on site. "The property owner must occupy either the principal unit or the accessory dwelling unit as their permanent residence." An owner absent "for a period of one year or less" may rent both units during that time.
• Ponding lots. If the lot is designated for on-site ponding, which holds storm water on the lot, the maximum lot coverage "including all buildings and impervious surfaces, is fifty percent." Impervious surfaces are paving and roofs that water cannot soak into.
• Setbacks. At least ten feet from any property line. On a rear alley with a right-of-way of twenty feet or more, the rear setback may be zero; on a narrower alley it may be five feet, or less with the traffic engineer's approval.
• Windows and privacy. An ADU taller than one story or fifteen feet may not have windows on a wall within ten feet of a property line next to a residential use, unless a fifteen-foot buffer of privacy trees from the City's approved tree list is planted fifteen feet on center (fifteen feet apart) along that line.
• Design. The ADU "shall resemble the principal unit in scale and character," with windows similar in type, trim style and proportions.

The phrase "in addition to" brings in Section 20.10.030, the general rule for accessory buildings. It places detached residential accessory buildings "not less than sixty feet from the front lot line" and at least five feet from the main building. It also caps the combined floor area of all detached accessory buildings on a lot at the more restrictive of "fifty percent of the gross floor area of the main building" or "forty percent of the area of the rear yard," while always allowing one building of up to four hundred square feet. Section 20.10.030 exempts ADUs from its one-story, fifteen-foot height limit and from its no-rear-setback rule, but it names no ADU exception to the floor area cap. Because subsection A applies "in addition to" Section 20.10.030, and Section 20.02.029 defines an ADU as an accessory building, a detached ADU must fit both the 800 or 1,200 square foot limit and the cap. Behind a main house of 1,400 square feet, fifty percent is 700 square feet. Ask the planning division how it applies the cap before you size the unit.

The Attached ADU in Detail

Subsection B permits attached ADUs "when they comply with the following." Its eleven rules repeat the lot area, floor area, bedroom, building code, alley access and height rules of subsection A. Three rules differ:

• the attached ADU "shall comply with all yard standards of the zoning district," the same yards as the main house;
• "A separate entrance shall be provided for the ADU";
• the unit must match the main house: "Roof pitch, siding material and color shall match the principal unit."

Subsection B has no owner occupancy sentence and no window privacy rule. Ask the City how it treats owner occupancy for an attached ADU before you plan one on a lot where no owner will live.

Parking, Guest Quarters and Renting

The Appendix C parking table has no row for an accessory dwelling unit. The ADU section itself speaks of "on-site parking" only in the alley access rule. A single-family detached house needs "2/dwelling unit" in Appendix C. Ask the City how many spaces it requires for the ADU before you design the site.

Guest quarters are a different use. Section 20.02.428 defines "Guest and/or employee quarters" as living quarters in a detached accessory building "for use by employees or guests of the occupants of the premises; such quarters having no separate utility meters, and not rented or otherwise used as a separate dwelling." Appendix A allows them as an accessory use in the residential districts, and Appendix C lists them at 2 parking spaces per dwelling unit. An ADU may be rented within the owner occupancy rule; guest quarters may not.

Short-term rentals have their own definition since Ordinance No. 019840 of February 3, 2026. Section 20.02.870.5 covers any residential use, including "a single-family home, duplex, an accessory structure," rented "for a period of less than thirty consecutive days," and says "the zoning standard for the base residential use shall apply to the short-term rental."

Duplexes: Where and on What Lot

Section 20.02.316 defines a duplex (two-family dwelling) as "a building designed or occupied as two dwelling units." Appendix A marks it "P" in R-4, R-5, A-1, A-2, A-3, A-4, A-O, A-3/O and A-M. The table below gives the Appendix B row for a two-family dwelling in each district that has one. Every duplex row requires that "a 20' driveway must be provided" with the front yard. Every row except A-O sets a 35-foot height limit; in A-O the maximum height equals the distance between the centerline of the abutting street and the face of the building.

Source: El Paso Municipal Code, Title 20, Appendix B, rows I.1, J.1, L.1, M.1, N.1, O.1, P.1 and R.1.

A-3/O allows a duplex in Appendix A but has no two-family row in Appendix B. Its "other permitted uses" row asks for a 6,000 square foot lot and "750 sf per dwelling unit; unless 3 or more stories, then minimum lot area of 600 sf per dwelling unit." Confirm with the City which row it applies to a duplex there.

Lot size can decide between the two. In R-5, a house needs 4,500 square feet and a duplex 6,000, while an ADU needs a 5,500 square foot lot. In R-1 to R-3A, where a duplex is an "X," the ADU is the only way to a second home without a rezoning. The zoning districts page explains a rezoning.

Duplex Parking and Selling the Two Halves

Appendix C row 13.09 requires "2/dwelling unit" for a duplex, so four spaces in all. Section 20.14.050 rounds any fraction of 0.5 or more up to the next whole space. Gravel or screenings, which is loose crushed rock, may be used for required residential parking only when the parking sits at least 20 feet from the front property line, or where on-site ponding or a permanent desilting basin serves the gravel area. The edge of a gravel area must be marked with edging, curbing or a hard surface.

A duplex owner may want to sell each half. Section 19.01.030 lets a recorded lot "in which a duplex is constructed, located in a district where duplexes are permitted" be divided by metes and bounds into two lots without a new plat, when one unit stays on each lot, a licensed Texas surveyor prepares the survey, no panhandle lot is created, and the survey is recorded with the El Paso County Clerk. A copy of the recorded survey must go with every later building permit application.

Where to Go Next

Related on VanPlex: the El Paso overview, ADUs in Texas, and building codes from duplex to fourplex.

Frequently Asked Questions

Official sources (checked October 2026)