The motorhome grey water system is a critical part of mobile living, helping you safely manage wastewater from sinks, showers, and appliances. This guide highlights five reliable grey water and waste tank options along with a practical buying guide to help you compare capacities, materials, fittings, and installation considerations. Each product below is designed to withstand the demands of travel, weather, and varying water usage while keeping your RV or motorhome compliant with standard plumbing practices.
| Product | Type | Capacity | Brand |
|---|---|---|---|
| WT-3161 Black Water Tank | Black Water Tank | 31 gal | classAcustoms |
| Class A Customs T-4600 | Fresh/Gray Water Tank | 46 gal | classAcustoms |
| Class A Customs T-2500 | Fresh/Gray Water Tank | 25 gal | classAcustoms |
| Class A Customs T-1000 | Fresh/Gray Water Tank | 10 gal | classAcustoms |
| RecPro 30/42 Gallon Combo Tanks | Fresh/Gray Water Tanks | 30 & 42 gal | RecPro |
Class A Customs WT-3161 31 Gal Black Water Tank
Manufactured in the USA from MDPE resin, this 31-gallon black water tank is designed for waste storage in RVs, motorhomes, campers, and tiny houses. It is intended strictly for waste water (black water) and features two 1.5″ NPT fittings and two 0.5″ fittings to accommodate common RV plumbing configurations. The tank is built to be vented and must be installed with appropriate piping. It emphasizes leak resistance and durability with standard installation practices. Note: Not suitable for fresh drinking water use.
Class A Customs T-4600 Fresh/Gray Water Tank
Designed for use with fresh or gray water, this 46-gallon tank is NSF-listed and built from approved materials for safety and reliability on the road. It accommodates dual water storage needs with a long dimension of about 42″ and a 14″ width by 18″ height, offering flexible placement inside an RV or trailer. Built-in fittings include two 1.5″ NPT outlets and two 0.5″ NPT fittings. It is intended for RVs, campers, and motorhomes where larger capacity is desired to minimize frequent dumping.
Class A Customs T-2500 25 Gallon Fresh/Gray Tank
This 25-gallon tank is suitable for both fresh and gray water in RVs, trailers, motorhomes, and tiny houses. It uses NSF-approved materials and includes built-in fittings: two 1.5″ NPT ports and two 0.5″ NPT ports. The tank dimensions are designed to fit various layouts, with careful attention to tolerance during manufacturing. The design supports rotation to adjust space and orientation for installation, making it a versatile option for mid-sized RVs needing more capacity than compact tanks provide.
Class A Customs T-1000 10 Gallon Fresh/Gray Tank
With a compact 10-gallon capacity, this Class A Customs tank is suitable for smaller motorhomes or areas with space constraints. It is NSF-approved for fresh or gray water use and features dual built-in fittings (1.5″ and 0.5″ NPT). The product emphasizes flexible placement and ease of installation, allowing the tank to sit on either side and to adapt to different RV layouts while maintaining a reliable water storage solution for shorter trips or compact vehicles.
RecPro Fresh and Gray Water Holding Tanks (30 & 42 Gallon)
RecPro offers a two-pack solution for RVs needing both smaller and larger capacity options to cover different days of travel. These tanks are designed to hold either fresh or gray water and have undergone pressure testing with NSF approval. The dimensions for the 30-gallon tank are approximately 34″ x 18″ x 12″ and the 42-gallon tank around 39″ x 18″ x 14″, accommodating a range of installation configurations. They provide essential support for longer trips or higher wastewater generation scenarios in motorhomes.
Buying Guide: Key Purchase Considerations for Motorhome Grey Water Tanks
- Tank type and use: Decide if you need a dedicated gray water tank (from sinks, showers) or a black water tank (toilet waste). Some products support both, but their labeling may emphasize one use over the other.
- Capacity needs: Match capacity to your typical travel duration, number of occupants, and water usage. Larger tanks reduce frequent dumping but require more space and weight considerations.
- Material and durability: Look for FDA/NSF-approved materials (typically MDPE or HDPE) that resist cracking, UV exposure, and chemical exposure from cleaners or septic additives.
- Fittings and compatibility: Check built-in fittings (NPT sizes) and whether you need additional adapters. Ensure the inlet/outlet locations align with your RV’s plumbing layout.
- Installation flexibility: Tanks that can sit on multiple sides or rotate to fit different spaces offer easier retrofitting in older RVs or compact trailers.
- Maintenance and cleaning: Consider tanks with smoother interior surfaces and compatibility with common RV treatments designed for gray water to prevent buildup and odors.
- Ventilation and venting requirements: Proper venting helps prevent pressure buildup and ensures smooth draining when the tank is in use.
- Regulatory and safety considerations: Ensure products meet local standards for potable water components when applicable and avoid mixing specs between fresh and waste water.
- Warranty and support: Look for manufacturers with clear warranties and accessible customer support for installation questions and replacements.
- Accessory compatibility: Odor control products and valves, vents, and dump valves may be needed to optimize grey water management beyond the tank itself.
Across these options, you’ll find a range of capacities from compact 10-gallon tanks suitable for small RVs to large 46-gallon tanks for extended trips. When selecting, prioritize compatibility with your vehicle’s space, the expected wastewater load, and how you plan to service the system on the road. A properly chosen tank helps maintain hygiene, reduces odors, and supports reliable wastewater handling for motorhomes and campers.