New Colorado Regulations for Gas Water Heaters: What Homeowners Need to Know Before 2026

What Is Changing?

The Regulation

Colorado’s new rule states that any gas water heater sold starting January 1, 2026, must meet Ultra-Low NOx standards. NOx emissions contribute to smog and poor air quality, especially in populated areas, so lowering emissions from gas appliances is an important part of improving public health.

The Purpose

The goal is simple:

✔️ Reduce smog-forming pollution
✔️ Improve Colorado’s air quality
✔️ Move toward cleaner, more efficient home heating solutions

Compliance Timeline

It’s important to note that the regulation applies only to new units sold after January 1, 2026. Any water heaters already in Colorado inventory before that date are exempt, meaning suppliers can still sell remaining stock even if it doesn’t meet Ultra-Low NOx requirements.

What Makes a Water Heater “Ultra-Low NOx”?

Ultra-Low NOx systems significantly reduce nitrogen oxide emissions and must meet strict testing criteria—similar to those established by California’s South Coast Air Quality Management District (SCAQMD). These units typically meet emission limits measured in ng/J for residential models.

They’re designed to be cleaner, more efficient, and better for the environment without sacrificing performance.

Brands Offering Ultra-Low NOx Options

Many manufacturers already offer models that comply with the upcoming Colorado standards. Some of the most common include:

A.O. Smith

Offers a full lineup of residential and commercial Ultra-Low NOx gas water heaters.

Bradford White

Produces certified Ultra-Low NOx models tailored to meet the new emission requirements.

Ruud

Their Professional Achiever Series includes heavy-duty residential Ultra-Low NOx water heaters that meet the new standards.

Lochinvar

Known for high-efficiency systems, Lochinvar offers Ultra-Low NOx tankless options that comply with Colorado’s new rules.

Why Upgrade Now Instead of Waiting?

You don’t have to wait until 2026 to make the switch. In fact, upgrading before the deadline has several advantages:

1. Avoid Cost Increases

Ultra-Low NOx units may cost more due to more complex manufacturing requirements. Buying early means avoiding potential price hikes once the new rules take effect.

2. More Product Options

After January 1, 2026, only compliant models will be sold in Colorado. Upgrading early gives you access to the full range of standard and Ultra-Low NOx systems, so you’re not limited in size, capacity, or brand.