MS4 Basics for Highway Supers

Published on August 10, 2025

What You Need to Know About Stormwater Regulations

If you’ve been hearing more about “MS4” lately, you’re not alone. Across the country, more municipalities and highway departments are being pulled into MS4 permit programs. If you’re a highway superintendent, it pays to understand what it means, and how it affects your department.

Here’s a quick rundown of the basics:

What is MS4?

MS4 stands for Municipal Separate Storm Sewer System.
It refers to the system of roadside ditches, culverts, storm drains, and pipes that collect stormwater runoff and send it, untreated, to local streams, rivers, and lakes.

In short: it’s the drainage system we build and maintain to move water away from roads and developed areas.

Why the Regulations?

Here’s the issue: when rain runs off roads, parking lots, and construction sites, it picks up pollutants; oils, fertilizers, sediment, litter, and more. If we don’t manage this runoff properly, those pollutants end up in our waterways.

The EPA and state environmental agencies require communities with MS4s to follow rules that help reduce this pollution. These rules are spelled out in an MS4 Permit.

Who Needs an MS4 Permit?

Generally, if your town or city is in an urbanized area, or if it’s growing fast, you may be required to comply with MS4 regulations. Many smaller towns are now being included.

What Does the MS4 Permit Require?

As a highway department, you don’t have to manage the entire MS4 program. Your town board or engineer typically oversees that.
But your department plays a big role in complying with several parts of it. Here’s what matters to you:

Public Education & Outreach

You may be asked to help spread the word about proper stormwater practices. Think signs at public works facilities or community clean-up days.

Illicit Discharge Detection & Elimination

You’ll likely be asked to help monitor ditches and pipes for illicit discharges, things like wastewater or chemical dumping that shouldn’t be in the storm system. If you spot one, report it!

Construction Site Runoff Control

If your crew or contractors disturb more than an acre of land, you’ll need erosion and sediment controls in place, such as silt fences, check dams, seeding, etc.

Post-Construction Stormwater Management

Some permanent controls, like rain gardens, detention ponds, or infiltration trenches, might be required in new developments. You may end up maintaining these features.

Good Housekeeping for Municipal Operations

This is the big one for highway supers: your own operations matter. The MS4 permit often requires:

Proper salt storage
Street sweeping where applicable
Training crews to prevent spills
Proper handling of equipment wash water
Keeping maintenance yards tidy and contained

In short: keeping pollutants out of the drainage system, starting with your own shop and fleet.

Why It Matters

Even if this feels like just another layer of paperwork, there are good reasons behind it:

Cleaner waterways benefit your community
Avoiding fines and penalties keeps the town out of trouble
Well-maintained ditches and drains help protect your roads from erosion and damage

And honestly, once you get good practices in place, staying in compliance isn’t that hard.

Final Tips for Highway Supers

Talk to your MS4 Coordinator – every town has one (often the engineer). Ask where you can help.
Train your crew – they need to know what’s expected.
Document what you do – simple records can help prove compliance.
Keep an eye out – you’re out in the field more than anyone. Spot problems early.

MS4 may sound bureaucratic, but it comes down to this: Don’t let pollutants wash off your roads into the nearest stream.
Good drainage work is already a core part of your job. MS4 just adds a few more things to watch for.

Tagged: Environment Regulations Municipalities MS4 Culverts Stormwater Management Drainage