Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Newmar Owner's Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 11-17-2009, 04:52 PM   #1
Join Date: Aug 2009
Posts: 35
Anyone ever added an extra grey water tank?

We do almost all dry camping. I would like to add an additional grey water tank. I know 65 gals. is not enough for our needs. I know I can bring along the honey wagon. But I thought if I could find some space I could add an additional
grey tank and pipe the tanks together.
I will also add an extra fresh water tank, but that's easy to do.
Do you think this could be done?
2009 Newmar Ventana 3942 2010 KTM 450 XCW
2010 Can-Am Outlander 650XT 2006 Yamaha TTR90
katoomer is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free! RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 11-17-2009, 06:01 PM   #2
Senior Member
GaryKD's Avatar
Newmar Owners Club
Join Date: Jul 2006
Location: Wellington, Florida
Posts: 13,599
Hi katoomer,
I do not know about adding an extra grey tank. However, consider adding a twist on waste valve. Go to
to see an example. If you coach is like mine, the grey and black tanks are on the same level. With this valve you could dump grey water into the black tank. In effect using the capacity of both tanks.

When your grey tank is full and the black is at 1/4, with this valve closed, open the grey then black tank valves. The tanks will even out. Close both tank valves. The process can be repeated until both tanks are full. When dumping, all three valves start closed. Open the twist on valve first. Then dump as normal.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
The Avatar Is Many Times Around The USA
Nobody Knows Your Coach Like Somebody Who Owns One Just Like Yours
GaryKD is offline   Reply With Quote
Old 11-17-2009, 06:06 PM   #3
Administrator in Memoriam
Route 66's Avatar

Newmar Owners Club
Retired Fire Service RVer's
Spartan Chassis
Join Date: May 2000
Location: Newark, DE
Posts: 25,898
I would think the basement is the only place to mount tanks.

Weight would be an issue, both for the strength of the basement floor and increased rear axle weight.

I don't recall anyone doing that.
Adios, Dirk - '84 Real Lite Truck Camper, '86 Wilderness Cimarron TT, previously 4 years as a fulltimer in a '07 DSDP

Route 66 is offline   Reply With Quote
Old 11-17-2009, 06:25 PM   #4
Join Date: Aug 2009
Posts: 35
I don't think I like the idea of a valve to fill our black tank with grey as then I would be worried about filling the black up.
I thought of mounting the extra tank between the frame rails not on the basement floor. then weight wouldn't be an issue for the floor.
I can't see adding a 40 gal tank at 8 lbs. per gal (320 lbs.) would be an issue for rear axle weight. I just have to find a place to put the tank so it is at the same level as the original grey tank.
2009 Newmar Ventana 3942 2010 KTM 450 XCW
2010 Can-Am Outlander 650XT 2006 Yamaha TTR90
katoomer is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Stopped up black tank tiger63 Travel Trailer Discussion 37 04-16-2017 12:05 AM
Grey Holding Tank ktmnoel MH-General Discussions & Problems 5 10-14-2009 09:47 PM
Grey water tank enlightenment moldmkr Winnebago Industries Owner's Forum 6 07-07-2009 09:19 AM
Grey/Black Water Tank Problem Hikerdogs Winnebago Industries Owner's Forum 3 12-28-2008 05:47 AM
grey water tank for Cobra Passport Jerry C Class C Motorhome Discussions 2 08-28-2006 12:17 AM

» Featured Campgrounds

Reviews provided by

All times are GMT -6. The time now is 11:24 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.