MSD's 2027 Rules for Property Owners: Private Laterals, Shared Sewers and Maintenance Access

For property owners, MSD's 2027 rules mostly tighten how private sewer lines are laid out and how they can be reached for maintenance. The private lateral rules now name sanitary, combined and stormwater laterals, so a private storm line crossing a property line has to connect directly to a public sewer just like a sanitary one. New private laterals still can't serve more than one property. MSD may limit or refuse connections to sewers it rates as high consequence of failure. And the draft adds a maintenance spacing target: street-access manholes no more than 1,200 feet apart, because MSD's cleaning trucks reach about 600 feet.

GreenFlow Solutions cleans, jets, camera-inspects, locates and smoke-tests sewer lines for commercial and residential owners in the St. Louis area. We don't write the rules or approve plans; MSD does.

Private laterals now explicitly include storm lines

Section 3.030.09, item 12 ("Private Lateral") of the 2027 draft says a private lateral (sanitary, combined or stormwater) that crosses a property line must be immediately and directly connected to a public sewer in an MSD easement or public right-of-way. The 2018 wording referred to a private sanitary sewer. Rules that carry forward:

• New private laterals may not serve multiple properties beyond the one where they start.
• Existing private laterals that run across several properties must be made public when they fail or when the properties are developed further.
• Private laterals should not run long distances in public easements or right-of-way, or cross them on long diagonals.

If you own a building whose lateral runs through a neighbor's lot, or a storm line that drains a few parcels, the 2027 wording makes it clearer that the rule reaches those lines too.

Shared private sewers on campuses and industrial sites

Where one owner holds adjacent parcels that can't be consolidated, MSD may allow a private sewer crossing those property lines, case by case. That shared sewer must be at least 8 inches, built to MSD standards, covered by a recorded private sewer maintenance agreement signed by each owner, and labeled "private" on the plans and MSD mapping. A maintained, inspected line is part of keeping that agreement.

Connections MSD may limit

New in the draft: MSD may limit or not allow connections to sewer assets it rates as having a high consequence of failure. The rules also ask designers connecting to old brick, non-reinforced concrete or other non-circular sewers to account for the material and condition of the existing sewer and provide a detailed connection design. A camera inspection of the existing line before design gives the engineer something to work from. See our sewer camera inspection and locating and mapping services.

Maintenance access: why manholes and continuity matter

• Manhole spacing. The draft adds that street-access manholes, meaning manholes in or next to a paved street MSD can reach, should be no more than 1,200 feet apart. MSD said its truck-mounted cleaning equipment reaches about 600 feet. Access is what makes a line cleanable.
• Continuous storm systems. New storm sewers must connect to the adjacent existing system. MSD said gaps between pieces of storm sewer create safety hazards, more blockages and more long-term maintenance.
• Locator wire. The draft rewrites the lateral tracer wire item to say sewer mains and laterals must comply with Missouri Revised Statutes 319.019 and 319.033.1. A line you can locate is a line you can find before someone digs into it.

Our sister company Kuesel explains the design side in its guide to storm sewer and inlet changes.

Combined sewer areas and backups

The rules carry forward the requirement that new or reused sewers and laterals in combined-sewer areas be separated into storm and sanitary lines out to the property line. Smoke testing and camera work help find cross-connections where storm water gets into a sanitary line. For new buildings, the draft also requires strapped plumbing for basement-level fixtures; our sister company Legacy Plumbing explains strapped plumbing under the 2027 rules.

What to do as an owner

• Know where your lateral runs and whether it crosses another property.
• If a private storm or sanitary line serves more than your parcel, ask your engineer how MSD's rules apply before you renovate.
• Keep a camera record of the line, especially before a sale, addition or connection.
• Put jetting and inspection on a schedule. See our preventative maintenance and hydro jetting services.

Call GreenFlow Solutions at 636-978-3478, Monday through Friday, 7:00 AM to 4:30 PM, or visit us at 854 Lone Star Drive, O'Fallon, MO.

General information, not engineering or legal advice. MSD, your engineer and the local plumbing authority set the requirements for your property.