Restroom Trailers

Plastic Holding Tanks for High-End Mobile Restroom Trailers

Trailer Holding Tanks Customized for Maximum Capacity & Space Efficiency.

As a leading plastic tanks manufacturer, we also specialize in the design and manufacturing of plastic holding tanks for high-end mobile restroom trailers.

We design and manufacture black water holding tanks, gray water holding tanks and clear water holding tanks for comprehensive bathroom trailer needs.

Trailer holding tanks can be customized to any shape or size.

Angles, radii, cut-outs and notches are no match for the experts at Miller Plastic Products! Our custom plastic tanks are designed and manufactured to maximize every cubic inch of space and every floor plan.


Our experience for helping you choose the right material for your particular custom plastic tank is just a phone call or click away.

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Our tanks are engineered using FEA (Finite Element Analysis) to maximize performance and allow for minimal bowing of the fabrication.

Plastic Holding Tanks Features


Increase Capacity


Fresh Water, Gray Water, Black Water


Internal Supports


Thread Milling into Tank Walls for Low Profile Plumbing Installations


Truncated Baffles Reduce Sloshing & Allow Complete Emptying


Custom Internal Plumbing Available - Including Castellated Pick-Ups

When it comes to plastic holding tanks that are reliable, rugged and customized for efficiencies, turn to the specialists at Miller Plastic Products.

We work closely with trailer manufacturers to ensure the very best solution is achieved.

Send us a sketch of your trailer holding tank & get your new custom plastic tank in 2 weeks or less!