Who Puts In the Culvert? The Montgomery County Answer

If your property is outside the Conroe city limits and the driveway crosses a bar ditch to reach the road, the first phone call is not to a concrete contractor. It is to your commissioner precinct.

This trips people up regularly, usually in one of two ways: buying culvert pipe before anybody has said what size it should be, or forming an approach before the pipe is set to grade. Both are avoidable, and both are expensive to unwind.

Why the county is involved at all

The crossing sits in the county road right of way, and the pipe underneath it carries ditch flow past your driveway. Get the size or the grade wrong and the ditch backs up, water crosses the driveway instead of going under it, and the fill under your approach washes out. The ditch is a piece of public drainage infrastructure and the county has a legitimate interest in what gets built into it.

The upside of that is real: the pipe gets sized against the drainage it has to carry, by somebody who knows the ditch, rather than against whatever diameter happened to be on the yard at the supply store.

Precinct 3

Precinct 3 publishes its culvert installation policy, and it splits the work clearly.

The resident:

• Contacts the Precinct 3 office for the correct culvert size
• Has the pipe on site and the installation location marked
• Contacts the office to enter the work into the system

The precinct then:

• Verifies the location is ready
• Submits the underground utility locate request through 811
• Sets the culvert to proper grade with cement-stabilised sand

Locates typically take forty-eight to seventy-two hours, and the precinct states it will set the culvert within three to seven business days under normal conditions, weather permitting.

Installation is charged per foot and invoiced on completion. The published rates are $25 per foot for a single culvert up to twenty-four inches in diameter and $30 per foot above twenty-four inches, with double culverts at $30 and $35 and triple at $35 and $40 respectively.

One line in that policy is worth reading twice: no driveway-type material is provided by the precinct, meaning no dirt, no rock, and nothing that goes on top of the pipe. The precinct sets the pipe. Everything above it is yours.

The precinct lists its contact number for culvert enquiries on that same policy page.

Precinct 4

Precinct 4 publishes a different arrangement. The property owner marks the driveway location before inspection, a Precinct 4 inspector visits the site and determines the required pipe size and the materials needed, and the property owner is responsible for installing the culvert and the driveway.

Same underlying goal, different division of labour, and a different cost structure for the homeowner.

Which means the address matters more than the county

Because the precincts differ, “what does Montgomery County require” is not a question with one answer. The useful question is which precinct covers this specific property, and then what that precinct’s published policy says. Ten minutes on the phone settles it.

The order to do things in

1. Find out which precinct covers the address.
2. Call them and get the culvert size for your crossing.
3. Buy the pipe, in that order, not before.
4. Mark the location and get on the schedule.
5. Let the locates clear and the pipe get set.
6. Then form and pour the approach to the set grade.

Doing step six before step five is how an approach ends up with a lip at the road, or a dip that ponds, or a slab that has to come out.

Why the approach cracks if you get this wrong

The approach is the hardest-working piece of concrete on a rural drive. It sits on fill placed over a pipe, and fill settles more than undisturbed ground unless it is compacted in thin lifts. It takes every vehicle at an angle, frequently loaded. And it sits where the road edge itself flexes under traffic.

Two things keep it intact: backfill compacted in lifts over the pipe, and extra thickness across the crossing. Both are cheap while the ditch is open and expensive afterwards.

Inside the city, it is a different route

If the property is inside Conroe city limits, none of the above applies. Work in the public right of way and anything tying into a city street runs through the City of Conroe, and Building Inspections and Permits is the department that answers it for a specific address.

The permits guide sets out both routes side by side, and the culvert driveways page covers the construction end of it.