St. Louis, MO Water Use Rules: Recycled Water Rules (2026)
Key Facts
- Grey water use
- Water closets, urinals, trap primers
- Grey water installer
- Licensed Master or Journeyman Plumber
- Reclaimed water installer
- Plumber or Master Drainlayer
- Homeowner rainwater exemption
- Tanks up to 65 gallons
- Enforcing office
- Office of Plumbing and Sewer Inspection
Summary
St. Louis requires grey water and reclaimed water plumbing systems to be installed only by a licensed Master Plumber, Journeyman Plumber, or Master Drainlayer under the city's Plumbing Code.
1. Grey water collected from plumbing drainage piping and used within a building for appropriate purposes i.e., water closets, urinals, trap primers, shall be installed as licensed and permitted by this Code by a licensed Master Plumber or a licensed Journeyman Plumber. 2. Reclaimed water delivered to a building site/premises by a public reclaimed water distribution system's series of mains and appurtenances...shall be installed as licensed and permitted by this Code by a Licensed Master plumber, a licensed Journeyman Plumber or Master Drainlayer.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 11).
Full Breakdown
St. Louis's Plumbing Code (2021 Uniform Plumbing Code as amended) treats grey water and reclaimed water as regulated non-potable systems, not do-it-yourself plumbing. Grey water collected from drainage piping and reused inside a building for water closets, urinals, or trap primers must be installed by a licensed Master Plumber or Journeyman Plumber. Reclaimed water piped in from a public reclaimed-water distribution system, including any on-site treatment and distribution, must be installed by a licensed Master Plumber, Journeyman Plumber, or Master Drainlayer. Only rooftop rainwater harvesting gets a homeowner carve-out, and only for tanks capped at 65 gallons each.
Violations & Fines
Installing grey water or reclaimed water plumbing without a licensed Master Plumber, Journeyman Plumber, or Master Drainlayer violates St. Louis's Plumbing Code and can trigger a stop-work order or permit denial.
Frequently Asked Questions
Can a homeowner install a grey water system in St. Louis?
Does connecting to a reclaimed water main need a licensed plumber?
Sources & Official References
Other rules in St. Louis
Compare St. Louis to another location·View the Missouri water use rules overview
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