Underground Infiltration System Typical Maintenance Requirements

Reporting Requirements

An initial installation certification (as-built) stamped by a Professional Engineer (P.E.) registered in the state of Wisconsin shall be submitted to the City Engineer upon completion of construction.  The as-built shall be of sufficient detail to show the system was properly constructed and is functioning as designed.  It shall include a statement by the certifying P.E. along with a marked-up drawing (if applicable) and photograph(s). 

An annual report shall be submitted via email to City Stormwater Management staff. The report shall include records of all inspections and maintenance performed for the year. Inspections shall be done every calendar year, with reports being submitted by June 1 of the following year.

Maintenance Provisions

Owner shall maintain records of installation, inspections, cleaning, replacement, and any other maintenance all in accordance with Chapter 37 of the Madison General Ordinances. Any alterations to approved underground infiltration system shall be reviewed and approved by the City Engineer. 

Regular inspections shall be completed at a minimum of once per year, typically in spring. This information will be used to determine the sediment build up within the system. Annual inspections should include the following:

• Locate the riser sections and cleanouts of the system. The riser will typically be 24" in diameter or larger.
• Remove the lid from a riser.
• Measure the sediment buildup at each riser and cleanout location. Only certified confined space entry personnel having appropriate equipment should be permitted to enter the system.
• Inspect each manifold, all laterals, and outlet pipes for sediment build up, obstructions, or other problems. Obstructions should be removed at this time.
• If measured sediment build up is 1-foot or more, cleaning should be performed at the earliest opportunity. A thorough cleaning of the system (manifolds and laterals) shall be performed by either manual methods or by a vacuum truck.
• All material removed from the system is considered hazardous waste and should be disposed of properly.

Inspect observation wells within 72 hours after a rain event greater than 0.5 inches.

after a storm event. Visually inspect and record observation of system. Maintenance is required when system shows standing water beyond 72 hours of rain event. Consult with your engineer to troubleshoot your next steps.

Infiltration Observation After Rain Event