Water is the main enemy of your house. We don't want roofs to leak, concrete blocks to show salt deposits, pipes to break, siding to fail or rainwater bumping up against footings or foundations. Buried downspout extenders are definitely more attractive and some runs need to be quite long to find a downgrade, so these caps that pop up when the pipes get full are very handy.
Here is a new product for sloped yards, called a drain wedge.
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