Forum Discussion

Huntindog's avatar
Huntindog
Explorer
Aug 03, 2019

Momentum 398M holding tank size

I am trying to find out what size black tank comes with the 1/2 bath option in the Momentum 398M.
They are closed now, and the dealer doesn't know.

TIA
  • Lwiddis wrote:
    See https://www.granddesignrv.com/showroom/2020/toy-hauler/momentum/floorplans/398m

    Fresh Water Capacity4
    157 Gal
    Grey Water Capacity
    104 Gal
    Waste Water Capacity
    52 Gal
    I have the brochure. It doesn't even mention the 1/2 bath as an option. The option appears in the build it feature on the website. Obviously a 1/2 bath in the garage cannot use the same tank as the main bath. That is why I had the question, which I now have the answer to. Two 53 gallon black tanks.
  • My present TT has two 42 gallon black tanks. This is an awesome setup for a TT. My goal was to equal that or better when moving to a TH. Grand Design seems to lead the pack in this area.
  • Oh man I would love black tanks that large. We were annoyed that the model year after our Impact doubled the tank size. We could boondock for over 2 weeks if we had ones that big. We never come close to filling the gray or running out of water.
  • Huntindog wrote:
    I finally got the answer.
    It has two 53 gallon Black tanks. The black tank for the 1/2 bath in the garage also serves as the grey tank for that bath.
    Not a big issue as it is the same as our present TT. We just do not use that sink.

    This was a major item on our check list. And it just moved the 398 to the top of our short list.


    That's a **** ton of Black capacity! You know the DW will relegate YOUR business to the 1/2 bath so you'll be golden.
  • I finally got the answer.
    It has two 53 gallon Black tanks. The black tank for the 1/2 bath in the garage also serves as the grey tank for that bath.
    Not a big issue as it is the same as our present TT. We just do not use that sink.

    This was a major item on our check list. And it just moved the 398 to the top of our short list.
  • Y-Guy wrote:
    From what I found a ew non half bath had 52 gallon black and 104 grety, a 2017 used w/half bath had 78 gallons black and 78 grey.

    Hope that helps.
    Pretty much what I found as well. I had previously crosssed the 398 off of my list because of the low 78 Black capacity, which was two 34 gallon tanks. It does appear that GD has upgraded the "M" class lately in some areas. Larger tanks being one of them. If the 1/2 bath, is now 52 gallon as well, it just shot to the top of my list.
  • See https://www.granddesignrv.com/showroom/2020/toy-hauler/momentum/floorplans/398m

    Fresh Water Capacity4
    157 Gal
    Grey Water Capacity
    104 Gal
    Waste Water Capacity
    52 Gal
  • From what I found a ew non half bath had 52 gallon black and 104 grety, a 2017 used w/half bath had 78 gallons black and 78 grey.

    Hope that helps.