Tiny House Plumbing

Users who are viewing this thread

BlakeR

New Member
Messages
8
Reaction score
0
Points
1
Location
Colorado
Hi,

I am building myself a tiny house on a trailer. I have been using old forum threads to answer questions and to learn how to install my plumbing system. I have reached a point where I have specific questions regarding my build and I am hoping to get some answers.

Thanks,
Blake

General Information
I am building in Colorado at an Elevation of 6500 Feet.
I am building on a 26' trailer with a 6" wood sub-floor.
My drain lines will exit below the trailer deck, so I want my p traps in sub-floor or under cabinets to prevent freezing.
I am planning on using 1 1/2" and 3" drain and vent lines.

Questions
Can I vent my bathroom sink, tub and toilet with a Studor Minivent under my bathroom vanity cabinet?
I plan on installing three Studor Minivents for my entire system. (kitchen sink and washing machine drain)
Can I drain my tub with in my 2x6 sub-floor with the following setup? Tub drain -- p trap -- 6" straight pipe -- 90 degree long turn -- exit below trailer deck into main drain

I have attached a sketch of my floor plan with idea idea of my drain plan.
 

Attachments

  • Tiny House Plumbing Questions.jpg
    Tiny House Plumbing Questions.jpg
    42.9 KB · Views: 615

WorthFlorida

Clinical Trail on a Cancer Drug Started 1/31/24. ☹
Messages
5,726
Solutions
1
Reaction score
982
Points
113
Location
Orlando, Florida
https://up.codes/viewer/colorado/ipc-2015

You start here with IPC codes. You’ll need to find out where you plan to use this tiny house if it is classed as a camper on wheels or a trailer type home that may require anchoring to a foundation. That will impact code requirements if any that are applied to tiny houses.
 

BlakeR

New Member
Messages
8
Reaction score
0
Points
1
Location
Colorado
https://up.codes/viewer/colorado/ipc-2015

You start here with IPC codes. You’ll need to find out where you plan to use this tiny house if it is classed as a camper on wheels or a trailer type home that may require anchoring to a foundation. That will impact code requirements if any that are applied to tiny houses.


Where I live it is considered a recreational vehicle. I will not have any building inspections. I will have traditional RV style hook ups for electrical, water and a sewer line. I work as a residential construction manger and I am familiar with many building codes, but I am not an expert in plumbing. As much as I respect the code, my main concern is proper functioning of the Tiny House, not code compliance.
Thanks,
Blake
 

Terry

The Plumbing Wizard
Staff member
Messages
29,946
Reaction score
3,460
Points
113
Location
Bothell, Washington
Website
terrylove.com
It would be better if it was the toilet as the last fixture.
Wet venting is for bathroom groups, so the lav could vent a tub and the toilet.
The kitchen sink needs it's vent, and so does the washer.
At least one atmospheric vent through the roof is needed when using AAV venting.
 

BlakeR

New Member
Messages
8
Reaction score
0
Points
1
Location
Colorado
It would be better if it was the toilet as the last fixture.
Wet venting is for bathroom groups, so the lav could vent a tub and the toilet.
The kitchen sink needs it's vent, and so does the washer.
At least one atmospheric vent through the roof is needed when using AAV venting.

Hi Terry,

Thanks for the response. If I need to install an atmospheric vent, I would prefer to do so on the exterior of the house, instead of through my walls. Is there an issue with venting on the outside of the house since my drains lines will be outside of my house as well? If running an exterior vent on the outside of the house, could I get away with running the vent to a certain height (4' above drains lines), instead of to the roof height? Does the vent just need to be above the fixture height (sink overflow)? If the toilet should be the last fixture, should I run the vent on the exterior of the house just past the toilet?
 

Attachments

  • Tiny House Plumbing Questions2.jpg
    Tiny House Plumbing Questions2.jpg
    44.2 KB · Views: 764

MACPLUMB

In the Trades
Messages
1,080
Reaction score
83
Points
48
Location
HOUSTON, TEXAS
Min vent size is 2" ! p-traps have to be located tight under the fixtures "NOT" below the flooring ! Exception Tub or Shower
 

Terry

The Plumbing Wizard
Staff member
Messages
29,946
Reaction score
3,460
Points
113
Location
Bothell, Washington
Website
terrylove.com
Last edited:

WorthFlorida

Clinical Trail on a Cancer Drug Started 1/31/24. ☹
Messages
5,726
Solutions
1
Reaction score
982
Points
113
Location
Orlando, Florida
Though this is classed as an RV, be careful not to create S Traps since they have more of a tendency to be siphoned dry.
 

BlakeR

New Member
Messages
8
Reaction score
0
Points
1
Location
Colorado
Washing machines take a 2" trap and standpipe.
Toilets use a 2" vent.
The purpose of venting above the roof is to disperse the sewer gas into the prevailing wind. Install it below your nose, and guess who gets to smell it?

Your drawing doesn't show much except that you plan to run pipes to those locations.

index.php


Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County


Thank you for the riser diagram. I will vent with 2" pipe and run my atmospheric vent to the roof.
Thanks
 
Last edited by a moderator:

BlakeR

New Member
Messages
8
Reaction score
0
Points
1
Location
Colorado
Though this is classed as an RV, be careful not to create S Traps since they have more of a tendency to be siphoned dry.

Yes! I've read that the run of the pipe past the p trap (trap arm?) needs to be twice the diameter of the drain before turning down again. My shortest trap arm run will be my tub p trap arm, where I need to bring it down in the shortest run possible.
 

BlakeR

New Member
Messages
8
Reaction score
0
Points
1
Location
Colorado
In the first image of the tub drain, I am going to try to run my p trap and trap arm in a 6" subfloor, before exiting below the trailer deck. I think this may be possible as my 1 1/2" p trap is about 5 1/2" tall.

In the second image, it shows the trap arm being twice the length of the drain diameter. Is this correct?
 

Attachments

  • 69cc318fbdf0053ec901d5b2f7691938.jpg
    69cc318fbdf0053ec901d5b2f7691938.jpg
    47.7 KB · Views: 388
  • aptrap.jpg
    aptrap.jpg
    36.1 KB · Views: 358

Reach4

Well-Known Member
Messages
38,795
Reaction score
4,413
Points
113
Location
IL
In the second image, it shows the trap arm being twice the length of the drain diameter. Is this correct?
That picture still shows an S-trap. The standpipe needs a vent before the drainage goes down after the trap. That vent could be an AAV.
 

BlakeR

New Member
Messages
8
Reaction score
0
Points
1
Location
Colorado
That picture still shows an S-trap. The standpipe needs a vent before the drainage goes down after the trap. That vent could be an AAV.

Is this now a p trap now that it is vented?
 

Attachments

  • anewptrap.jpg
    anewptrap.jpg
    30.7 KB · Views: 686

Reach4

Well-Known Member
Messages
38,795
Reaction score
4,413
Points
113
Location
IL
Yes. 2 inch pipe for a washer standpipe.
 

Reach4

Well-Known Member
Messages
38,795
Reaction score
4,413
Points
113
Location
IL
If you run 2 inch pipe from the roof for the lavatory, that will probably also vent the downstream toilet.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks