A modular underdrain system is disclosed. The modular underdrain system may comprise an intermediate modular component having a first peripheral side including a first mating portion and a second peripheral side including a second mating portion. The second mating portion may be sized and shaped to engage with a first mating portion of an adjacent modular component. A modular component chamber may be bounded by an underdrain floor side and an internal side. The underdrain floor side may comprise a plurality of slots. The metering pipe is sized to be positioned within a metering pipe opening in the internal side with a distributor head positioned within the modular component chamber. The metering pipe may comprise a set of one or more remote orifices and a set of one or more proximate orifices.