Private Culvert Owner Resources

Damaged private culvert
Damaged private culvert

Driveway culverts like the ones shown above must be repaired or replaced by the property owner. A revocable encroachment permit is required for all work in the County Right of Way, including replacing private driveway culverts. Visit the encroachment permit webpage.

Summary

Just like a car needs an oil change regularly and a house needs a new roof every few decades, private culverts must be kept clear of debris and replaced before they rust or collapse. Private property owners are responsible for maintaining their own culverts and stormwater drainage systems (SWDS). 

The regulatory authority, responsibility, and management of stormwater drainage systems are found in the Whatcom County Development Standards, Chapter 2, Stormwater Management, Section C

Contact Us

  1. Engineering Services

    5280 Northwest Drive
    Suite C
    Bellingham, WA 98226

    encmail@co.whatcom.wa.us
    Phone: 360-778-6220
    Fax: 360-778-6221

Common culvert problems:

  • Undersized, unable to accommodate water flow.
  • Crushed, damaged, or rusted.
  • Full of sediment or vegetation.

Benefits of Culvert Maintenance

  • Prevents and reduces the risk of flooding.
  • Improves habitat for fish and other aquatic species.
  • Extends the life of the culvert through proper maintenance.
  1. When to Replace A Culvert
  2. Who Can Replace a Culvert
  3. Relevant Documents

Two key factors determine when to replace a culvert. 

  1. Condition – Culverts have a finite lifespan and eventually need to be replaced. When the structure can no longer convey stormwater, even after cleaning, or it presents a danger to the travelling public. Visually inspect your culvert for signs of damage or failure. Different pipe materials indicate failures in different ways:

    • Concrete – Look for separations, cracks or collapse of tiles altogether. Separation of tiles can cause backfill material to fall into the pipe and prevent the flow of water. Potholes on the surface above a pipe indicate a loss of backfill material due to separations or collapse.
    • Metal – Look for pitting and rusting, typically at the bottom of the pipe. Inspect the shape of the pipe. Significant deviation from the original shape indicates a failing culvert. 
    • Plastic –  Inspect the sidewalls for cracks or discoloration. Inspect the shape. Similar to metal, corrugated plastic pipes require the backfill material to support the sidewalls to handle heavy loads. A pipe in good condition will be mostly round and not oval shaped.
    • Regardless of the material, all pipes should be inspected for root invasion. Roots in the pipe are a sign that the structure has failed and should be replaced. 
    • In addition to the pipe itself, inspect the headwalls of your culvert to prevent scouring and erosion of material around the pipe. Excessive scouring indicates an undersized pipe and replacement should be considered. 
  2. Time of Year – The right time to replace your culvert depends on site conditions. It's possible to replace a culvert in wet conditions, but it is always easier and the finished product better, when completed in dry conditions. Some ditches are also classified as fish habitat and require work to be done between July 15 and September 30.