An underdrain is a concealed drain with openings through which the water enters when the water table reaches the level of the drain and is located below a filter bed. Tonka Water offers several underdrain options to meet your filter needs.

BLEU™ Underdrain
The BLEU™ underdrain is a low profile stainless steel dual parallel underdrain typically used in concrete construction. BLEU™ eliminates dead zones between laterals, achieving complete media turnover during backwash.

Uni-Cast™ Monolithic Underdrain
The Uni-Cast™ monolithic underdrain is typically used in municipal gravity filters for potable, wastewater, and pretreatment systems. Based on the size and design specifications, we will design and provide all the components required to construct the monolithic underdrain onsite.

Header Lateral Underdrain
This common underdrain type, used primarily in pressure vessels, has a common header pipe going down the middle of the filter with a series of lateral pipes extending from the header.
