Here's the kind of efficiency that Taylor quotes for drop inlets. It's not very impressive. Taylor's figures for other BMPs are much better but not very encouraging. Infiltration, according to Taylor, is a popular solution because it treats the discharge on the site. Then, other more ineffective and expensive BMPs aren't needed.
Infiltration is most effective in relatively permeable soils.
Yet, there are questions about their effect on groundwater. Phosphorus bonds quickly to soils and can be removed with infiltration. Even so, dissolved phosphorus is found in ground water in the Tahoe Basin. Nitrogen is very mobile in water and will hardly be affected. Also infiltration devices can be clogged and not do the job.