McKinney Utility Availability Study: What Developers Need Before Submitting a Plat in Collin County’s Fastest Growing City

Why isn't a water line at the frontage enough?

Size, pressure plane and condition decide service, not location. McKinney's Engineering Design Manual (Revision 7, adopted May 5, 2026) does not allow connections to substandard mains. The Director of Engineering judges that by size, material, condition, pressure and flow rate, and the manual warns that offsite improvements may be needed to serve the site.

The manual also requires every new addition to the water system to have two adequate points of connection, so one tap on the frontage line rarely settles the question.

Then there is the pressure plane. The city runs three: the 794, 850 and 920 Service Areas, with a proposed 840 Service Area to be fed from the 794 through a booster pump station. If the city lets you connect outside your own plane, the minimum static pressure is 50 psi, and a temporary booster or pressure reducing valve may be required.

What does McKinney require before a plat?

Preliminary utility plans, and sometimes formal studies. Under Section 305A of the McKinney Unified Development Code, a preliminary plat is required when a development is phased. It is also required for single-family, duplex, triplex or quadplex lots on unplatted land when the plat has more than four lots, lots without street frontage, a new street, or an extension of municipal facilities.

The application includes preliminary utility plans and preliminary drainage plans. For multi-family and non-residential projects inside the city, the preliminary plat cannot be submitted until the site plan is approved.

The Director of Planning approves a preliminary plat when, among other things, its utility layout follows the Engineering Design Manual and it shows evidence of adequate public facilities. The code also lets the Director of Engineering require utility analyses. When those come with a preliminary plat, they must be reviewed and substantially complete before the plat is approved.

The design manual adds two triggers. A water or wastewater study is required where the proposed land use density exceeds the previously zoned use or density, and a sanitary sewer basin map can be required to show capacity downstream. We covered the rest of what changed in McKinney's 2026 Engineering Design Manual separately.

How does the Texas plat clock change the timing?

It leaves no room to work out capacity during review. Under Texas Local Government Code Chapter 212, Section 212.009, the city must approve, approve with conditions, or disapprove a plat within 30 days of filing. Section 212.0091 requires a written statement of each condition or reason, with the law it rests on.

Section 212.010 ties approval to the city's general plan for public utility facilities and the extension of water and sewer mains. On a 30-day clock, an open capacity question has little room to become anything but a condition or a disapproval. Bring the answer with the plat.

What fire flow does McKinney require?

At least 1,500 gpm for single-family areas and 3,500 gpm for multi-family, commercial and industrial areas. The design manual sets fire flow by Appendix B of the International Fire Code as amended by the city, at a minimum residual pressure of 20 psi under combined fire and maximum daily demand. Buildings over 75,000 square feet may need more, per the Fire Department.

The state floor is 30 TAC §290.44(d): 35 psi at all points at 1.5 gallons per minute per connection, and 20 psi under combined fire and drinking water flow where the system provides firefighting.

Main size follows from that. In multi-family projects, a main longer than 600 feet between intersecting mains, or feeding more than one hydrant or fire line, must be 12 inches unless the city's modeling consultant verifies an 8-inch main, at the developer's expense. Here is how a fire flow analysis works for a Texas subdivision.

What decides sewer capacity in McKinney?

The whole basin downstream, not the line next to you. The manual requires gravity mains, and allows a lift station only with the Director of Engineering's approval after every other way to move the flow has been investigated. Flows stay in their own drainage basin unless the Director approves otherwise.

Collection systems must carry the peak wet weather flow from the entire service area, including offsite areas. Basin delineation uses NCTCOG, LIDAR or surveyed contours at 2-foot intervals or less; USGS topography is not accepted. Mains with service connections are designed no more than 70 percent full, and interceptors 80 percent full.

Treatment is regional. McKinney is a member of the North Texas Municipal Water District's regional wastewater system, and the city's development permit checklist lists an NTMWD connection application where one applies. Inside the city's CCN, the manual authorizes no other treatment plant except a septic system serving one home.

What if the adequate line is offsite?

You build it, and maybe get some of it back. Section 301E of the code says public improvements are built at the developer's sole cost, to, upon and across the property and through to adjacent properties as the Director of Engineering finds necessary. They must follow the city's Water Distribution System Master Plan and Wastewater Collection System Master Plan, which you request from Engineering.

Plan for offsite easements early: the city lists offsite easement documents among the items due before a development permit. Where the city wants a line larger than your project needs, Section 302 allows a facilities agreement for pro rata reimbursement or city participation. Reimbursement is paid only from money the city later receives from development of the surrounding area.

Is your McKinney site ready for a plat submittal?

Ready means every answer below is yes.

1. Do you have the city's pressure range map for the site at maximum daily demand?
2. Have you identified two adequate points of connection, neither on a substandard main?
3. Does the model deliver the required fire flow at 20 psi residual for your land use?
4. Have you checked the sewer basin and downstream capacity, including offsite flows?
5. Can the site drain by gravity, or is a lift station justified against every alternative?
6. Are offsite extensions, easements and any facilities agreement scoped?
7. If your density exceeds the current zoning, have you asked Engineering about a utility study?
8. Has the Director of Engineering said which studies must come with the preliminary plat?

A note on limits: this is general education from McKinney's published Unified Development Code, its Engineering Design Manual Revision 7 and state rules as of October 2026. The city's master plans and hydraulic models are not posted publicly, so confirm the answers for your site with the Engineering Department.

Frequently asked questions

Will the City of McKinney run the study for us?

Not the whole thing. The manual has the engineer get the pressure range map and required main sizes from the Director of Engineering, and for some multi-family and non-residential mains the city's modeling consultant checks sizing at the developer's expense. Turning that into a yes or no for your program is your engineer's work.

How long does a McKinney preliminary plat approval last?

A final plat for all or part of the area must be submitted within 180 days, or the approval is void. The Director of Planning can grant a first extension of up to 90 days, and the Planning and Zoning Commission considers any further ones.

I'm a homebuilder under contract on a McKinney tract zoned for single family, and I want to add townhomes. Do I need a utility study before I file?

Probably. The manual requires a water or wastewater study where the proposed density exceeds the previously zoned use, as the Director of Engineering determines. Its own demand table puts townhomes at 12,670 gallons per acre per day of maximum daily demand, against 6,048 for R6 single family, so the city will want to see the system carry it.

I'm the civil engineer on a McKinney commercial site that sits on a pressure plane boundary. Can we tap the main across the street if it is in the other plane?

Only if the Director of Engineering allows it, and then the minimum static pressure is 50 psi with a temporary booster or pressure reducing valve possibly required. Where planes are split by a street, the manual calls for a main on each side for its own plane.

Related resources

• NTMWD Connection vs. Private Treatment: The McKinney Developer's Guide to Choosing the Right Wastewater Path
• Water Storage and Pressure Zone Design for McKinney's Rolling Terrain: Engineering for Collin County Topography
• Impact Fees and CIP Timing: Why Phasing Costs Blindside Developers When the Capital Improvement Plan Schedule Does Not Match Their Build Out
• CCN Territory Disputes in Collin County: What to Check Before Land Crosses a Water Provider Boundary

Planning a plat in McKinney without a capacity answer?

We confirm what the city's water and sewer system can deliver to your site, and what you will have to build, before the layout is locked.

We specialize in:

• Site feasibility and utility due diligence
• Water distribution modeling and fire flow analysis
• Wastewater collection and lift station design
• Offsite utility extension design and easement coordination
• Site civil design for land development
• Construction administration for public improvements

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com