Once past the construction phase and into the operational phase, owners should be encouraged (actually required) to do routine maintenance. Typically, this would be dry-sweeping the entire parking lot, not just the pervious concrete. The frequency will depend on things such as the individual site, the amount of traffic, and the sedimentation sources. Basically, the parking lot should be swept whenever there is obvious junk on the surface, such as leaves, twigs, dirt, or sand.

Asphalt parking lots are especially prone to producing their own sediment from normal wear and tear. This surface raveling of the asphalt is basically sand size particles consisting of asphalt chips and actual sand that is dislodged under normal traffic. This sediment will show up pretty quickly in the leading edge of pervious concrete sections and is easily identified because it is primarily black or dark gray in color, as opposed to the brown or reddish color for dirt sediments. Concrete parking areas most likely produce some of this in-service surface raveling as well, but I suspect there is less volume of this material and it will be harder to distinguish, as it will be the same basic color as the pervious concrete.

Maintenance plan

Routine maintenance (see "Pervious Concrete Maintenance Summary" on the next page) captures or removes sediment particles before they can infiltrate deeply into the pervious concrete matrix. It starts with regular dry-sweeping and moves up to dry-vacuuming the surface.

For more aggressive maintenance, use pressure washers to dislodge particles in the top portion of the pervious and to either flush them off of the pavement or through the pavement. For many cases where routine sweeping has been neglected, this may do the trick and restore adequate infiltration to the pavement.