MarkC Posted August 2, 2022 Share Posted August 2, 2022 Could I fill the black tank through the wash down port. Then drain into a container. And, pump into water tank through boondock port at rear of trailer? Link to comment Share on other sites More sharing options...
Moderators Mike and Carol Posted August 2, 2022 Moderators Share Posted August 2, 2022 Assuming a composting toilet… There is a backflow valve in the line for the black tank flush and the flush line enters the black tank near the top, so that won’t work. The only other way is through the black/gray sewer hose that exits at the rear of the trailer. Not very sanitary. Finally, I’m sure the plastic used in the black tank is not drinking water safe. I would say no. Mike 1 3 Texas Hill Country | 2016 Elite II #135 | 2020 Ram 2500 6.7L Link to comment Share on other sites More sharing options...
Frank C Posted August 2, 2022 Share Posted August 2, 2022 The black tank drain valve and gray tank drain valve both share the common drain pipe in the Ollie. The drain valves do not seal perfectly, so there’s a risk of cross over leakage/contamination between those two tanks. I wouldn’t use the black tank for fresh water unless it was completely isolated from the gray tank. And on Olivers with the composting toilet, I’m not sure if Oliver still cuts the hole in the top of the black tank where the toilet flange is installed with the flush toilet option. There may be a 3” diameter hole on the top of the black tank, even with the composting toilet, since Oliver does try to make it easy to switch from one toilet option to the other. 3 Link to comment Share on other sites More sharing options...
John E Davies Posted August 2, 2022 Share Posted August 2, 2022 The upper black tank hole is plugged when there is a NH installed, no worries there. ABS can be used for potable water, the main drawback is it is never to be installed in direct sunlight, not a problem in an Ollie. By RV CODE you should not use the black tank, in reality it would work fine, as long as you disconnect it from the main 3" waste pipe under the front dinette seat, and cap off the tank outlet tank. Install a PEX drain line with shutoff valve and also a BIG PEX overflow pipe from the top of the tank, exiting out the bottom hull. And be sure to go under the bath sink and disconnect and cap the 1 1/2" black tank sewer vent, otherwise the two systems are still physically connected. While you are under there, cap off the fresh water line going to the toilet, so you don't have to keep winterizing that unused section of pipe. I have been thinking about this for five years but never did it. Please go ahead and post pics, we like research and development pioneers here. 😉 Small projects tend to get big in a hurry when you figure out all the angles. https://westernrooter.com/abs-vs-pvc-pipe/ John Davies Spokane WA 5 SOLD 07/23 "Mouse": 2017 Legacy Elite II Two Beds, Hull Number 218, See my HOW TO threads: Tow Vehicle: 2013 Land Cruiser 200, 32” LT tires, airbags, Safari snorkel, Maggiolina Grand Tour 360 Carbon RTT. Link to comment Share on other sites More sharing options...
VBistro Posted August 2, 2022 Share Posted August 2, 2022 I hadn't thought about using the black tank for fresh water, but I *did* procure everything I need to use the black tank as extra gray storage. Most places we boondock have water nearby that we can filter with a filtering jerrycan and pump into the fresh tank in boondock mode, but I often find ourselves butting up against gray tank limits. If you haven't see this yet, it's clever! 1 3 MaryBeth Boulder, CO 2022 Elite II #953 TV: 2021 Ford Expedition Max Platinum, Max Tow Package Link to comment Share on other sites More sharing options...
Moderators SeaDawg Posted August 2, 2022 Moderators Share Posted August 2, 2022 In a few words, don't do it. Grey water fine. Fresh water could be easily contaminated, and the black tank is not rated for potable water. 5 2008 Ram 1500 4 × 4 2008 Oliver Elite, Hull #12 Florida and Western North Carolina, or wherever the truck goes.... 400 watts solar. DC compressor fridge. No inverter. 2 x 105 ah agm batteries . Life is good. Link to comment Share on other sites More sharing options...
NCeagle Posted August 3, 2022 Share Posted August 3, 2022 On 8/2/2022 at 2:04 PM, Frank C said: ...And on Olivers with the composting toilet, I’m not sure if Oliver still cuts the hole in the top of the black tank where the toilet flange is installed with the flush toilet option. There may be a 3” diameter hole on the top of the black tank, even with the composting toilet, since Oliver does try to make it easy to switch from one toilet option to the other. Just an fyi that obviously may change from trailer to trailer and year to year: We have hull 688 (2020) with the composting toilet option out of the factory. Although the hole is there in the fiberglass floor under our Nature's Head, our black tank has no drilled holes on top - or anywhere else. It is also properly vented so you can fill it through the outside port (I use it for extra grey water storage only). 2 2020 Elite II, Hull 688 --- 2021 Silverado 2500HD, 6.6L Duramax Diesel Link to comment Share on other sites More sharing options...
John E Davies Posted August 3, 2022 Share Posted August 3, 2022 3 hours ago, NCeagle said: It is also properly vented so you can fill it and empty it through the outside port (I use it for extra grey water storage only). How do you empty it through the outside port? Or was that a typo? FYI if you overfill it, it will flood the bathroom, just like the main grey tank, ultimately coming out over the top of the door sill. Do you pump out of a bucket to keep track? John Davies Spokane WA 1 SOLD 07/23 "Mouse": 2017 Legacy Elite II Two Beds, Hull Number 218, See my HOW TO threads: Tow Vehicle: 2013 Land Cruiser 200, 32” LT tires, airbags, Safari snorkel, Maggiolina Grand Tour 360 Carbon RTT. Link to comment Share on other sites More sharing options...
NCeagle Posted August 6, 2022 Share Posted August 6, 2022 On 8/3/2022 at 9:56 AM, John E Davies said: How do you empty it through the outside port? Or was that a typo? FYI if you overfill it, it will flood the bathroom, just like the main grey tank, ultimately coming out over the top of the door sill. Do you pump out of a bucket to keep track? John Davies Spokane WA Hey John, yes that was a typo. I only fill it through the outside port. I avoid overfilling it using a stopwatch and the See Level monitors. I'll run it for 2.5 minutes because my pump runs pretty close to 5 gallons per minute. Then I'll check my grey and black See Level monitors and it confirms about 12-13 gallons into the black tank. I don't push it to 15 gallons for fear of pushing water up the vent and into places it doesn't belong. Yuck. 🙂 4 2020 Elite II, Hull 688 --- 2021 Silverado 2500HD, 6.6L Duramax Diesel Link to comment Share on other sites More sharing options...
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