quattroworld

free for a very long time. They clog up when other things, or areas drain to them bypassing the filter and stone, like downspouts, driveway channel drain, etc.. That's why its super important not to direct those items to the same pipe and drain as a perforated pipe and stone system around your foundation. Also, if provided a clean out, long term, it is pretty simple to clear and maintain them in any case.

I have dug up drain tiles around foundations of other configurations with no/little stone, and or the old clay tiles and yes they are basically useless, but a nicely detailed system works.