How to Inspect the Plumbing Systems of Mobile Homes, Double wides, Trailers

Mobile home plumbing system: fixtures, water supply, drainage, sewage system inspection guide
- Common mobile home plumbing system defects at plumbing pipes, fixtures, water heaters, oil tanks, oil piping or gas piping
- Safety and building codes for mobile homes
Questions & Answers about mobile home & double-wide plumbing systems: inspection, diagnosis, repair, or replacement of mobile home plumbing
References

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How to Inspect Mobile Homes or Manufactured Housing for Plumbing System Defects: detailed procedures, defect lists, references to standards for mobile homes, trailers, double-wide home plumbing water supply & drain piping and oil or gas fuel piping. Mobile home septic systems are also addressed.

Doublewide, Mobile Home (Caravan) or Trailer Plumbing System Defects & Hazards

Ver.3.5 - 04/25/07, updated through 2012 - Steve Vermilye, New Paltz NY and Daniel Friedman, Poughkeepsie NY, Hudson Valley ASHI Chapter Seminar, Newburgh NY, January 4, 2000, NY Metro ASHI Fall 99 Seminar, Holiday Inn Crowne Plaza, White Plains NY, October 2, 1999. Our page top photo shows our associated Steve Vermilye inspecting an on-ground, tipping, heating oil tank at a mobile home occupied by farm workers in Ulster County, N.Y.

GENERAL PLUMBING - Comments for Mobile Home Inspectors

36% of mobile homes report problems with plumbing (C. R. survey)
most common complaint according to C. r. - 1/3 homes have problems;
Low quality sinks, tubs, showers, faucets (molded plastic faucets, fixtures; porcelain or acrylic preferred)
no shutoff valves especially at toilets in mobile homes and trailers
leaks damage structure, especially with use of particle board sub flooring.

SUPPLY PIPING - Mobile Home Supply Piping Defects and Plastic or polybutylene water supply piping failures, leaks, and litigation

PB (polybutylene with mechanical fittings) Piping leaks: especially in South, for example trailers and double-wides throughout Florida that were piped with this material - per M Cramer. See "Polybutylene Piping: Time Bomb?" Daniel Friedman, Journal of Light Construction, August 1996 [Technical Q&A].
Plastic Supply and Drain Piping Failures: leaks, lawsuits, settlements

If plastic water piping is installed, such as polybutylene water supply piping, it should be at least 18" from the water heater.
New mobile home and trailer units: 3/4" supply piping, min 6" off ground; shutoff valve required;

Freeze Protection Suggestions for Mobile Homes, Double-Wides and Trailers:

Note on use of heat tapes on plumbing or oil piping: The US CPSC recommends that heat tapes be connected to a GFCI-protected electrical receptacle (or on newer wired-installations AFCI circuits) for fire safety but HUD rules do not allow connection of the heat tape to GFCI because they don't want to risk frost damage: so note conflict between frost damage and life-safety concerns. Heat tapes used on exposed plumbing at extra risk of freezing, e.g. below the units.
If mobile home supply piping has frozen, burst, and leaked into the structure, you'll need to remove and discard any wet insulation - or else face a mold problem.
Simply adding insulation, in any amount is by itself unlikely to be sufficient to protect a mobile home from freezing if it's left unattended with heat off. Rather people design the plumbing to be drained when the home is left.
If the trailer or mobile the home is occupied then you'll need to look carefully at supply pipe routing and maybe even add heat in some areas. We dislike heat tapes - as they can be unreliable and possible fire hazards, but they can work in some cases.

High-quality plumbing pipe heating tapes that can be crossed over one another without melting and shorting out (fire hazard) are available. Of course if the home loses electrical power this solution won't help much. To reduce the mobile home fire risk when using heat tapes, use metal-braid shielded heating cables connected to a GFCI protected electrical outlet so that if the heating tapes short out the circuit will trip.

Plumbing below a mobile home subject to freezing (C) Daniel Friedman

Trailer & mobile home water entry lines (and some drains) are often exposed to freezing below the unit - (photos at left and above left and right).
If the mobile home water supply is provided by a pump and the pump is found to have cracked (and the home is located in a climate where freezing weather occurs, pump cracking probably means it froze and was not drained or protected from freezing.
If mobile home drains are freezing the same frost protection or heating concerns need to be addressed as we've just listed.
Open drains or leaky connections (crawl)
Leaky supply main (crawl)

DRAIN WASTE VENT - Mobile Home & Trailer Drain Waste Vent Piping Defects

Mobile home drain onto ground surface (C) Daniel Friedman

Mobile home bathroom (C) Daniel Friedman

Multiple repairs indicates freezing pipe history (C) Daniel Friedman

In freezing climates, failure to protect water supply piping (& drain traps) from freezing. If you see supply piping with a stunning number of small parts and solder joints and repairs (photo at left) that may indicate a history of frozen pipes in that unit.
Heat Tapes - use metal-braid shielded type connected to GFCI so if there is an electrical short the circuit breaker will trip or fuse will blow

Plumbing drains in mobile home, leaks, floor damage (C) Daniel Friedman

Plumbing drains added (added laundry or bath) not under unit or ? (photo at above left shows a laundry drain spilling onto the yard surface by the mobile home)
Leaky traps rot walls and floors faster than conventional construction especially where OSB or chipboard was used for subfloor material in the mobile home or trailer
Leaky traps rot walls and floors faster than conventional construction especially where OSB or chipboard was used for subfloor material in the mobile home or trailer

Our photo (left) illustrates an area of plumbing drain leaks below the sink in a doublewide home - rot destroyed the subfloor, invited carpenter ants into the structure, and soaked insulation.

Improper and non-functional tub controls and spout in a mobile home (C) Daniel Friedman

Plumbing fixtures with non-functional and / or inadequate parts such as these leaky tub/shower controls and missing tub spout in a mobile home.
Look for plumbing leaks into the crawl area;
Look for proper plumbing drain slope 1/8" /ft, and support (no less than 4ft o.c.), and
Check the direction of plumbing fittings, and proper adhesive (DWV for PVC, ABS or both);
Damaged plumbing fixtures, leaky sink traps, unsafe electrical receptacles or no GFCI's in bathrooms and kitchens - our photo at below left shows a leaky sink, improper (down-sloping) drain connection to a laundry at left of the sink tailpiece, and leaks that have created a mold problem in this mobile home.
Amateur plumbing work and leaks leading to structural damage - photo at below right shows the value of finding access to tub and shower plumbing and a history of leaks.

Leaky sink and mold in mobile home (C) Daniel Friedman

Leaks at tub in mobile home (C) Daniel Friedman

MOBILE HOME & TRAILER or DOUBLE-Wide Heating FUEL SUPPLY Defects & Concerns, gas and oil piping

Mobile home and trailer gas piping: crossover flex connector at mate line of adjacent units
LP tank or oil tank location - per manufacturer and code;
Gas and oil shutoffs required per usual locations - at but not inside the appliance cover
Gas meter base: if a gas meter is installed, the manufacturer may specify the minimum distance from the gas inlet; because installation is done on limited budget it's often by people who are not trained and don't know these or other safety requirements
Gas piping supplying LP gas to the mobile home, trailer, or double-wide home is often not protected from damage (photo at left - Steve Vermilye)

Warnings about using heat tapes on mobile home water or drain pipes or on heating oil lines

Heat Tapes - use metal-braid shielded type connected to GFCI so if short will trip. Heat tapes, especially the non-shielded types, short and start fires, especially if crossed over themselves or otherwise improperly installed.

Mobile home oil tank defects, problems, repairs

Oil tank fuel gage using a soft drink bottle (C) Daniel Friedman

Oil tank support (often falling or in ground-contact) see our photo at page top
Oil tank gauges and fill and vent piping - exposed to water entry from roof spillage or, as in our photo, from a makeshift repair to a fuel gage or other tank connection

WATER HEATER Defects & Safety Hazards in Mobile Homes, Trailers, Double-Wides

In freezing climates, failure to protect water supply piping (& drain traps) from freezing. If you see supply piping with a stunning number of small parts and solder joints and repairs (photo at left) that may indicate a history of frozen pipes in that unit.
Heat Tapes - use metal-braid shielded type connected to GFCI so if there is an electrical short the circuit breaker will trip or fuse will blow
Gas-fired water heater located in in sleeping areas
Gas or oil fired water heaters in a tight utility closet without adequate combustion air
Electric (usually) water heaters often with bad wiring connections
Water heater located outdoors (not a location supported by the equipment) (photo below left)

Mobile home water heater (C) Daniel Friedman

Plumbing valves, pipes, not proteted from freezing
Water heaters located in closets accessed only from outside, never inspected, heaters leaky or unsafe because the water heater has tipped on a rotting floor (photo at below left)

Water heater relief valves in mobile homes: to hidden location (below trailer, can't see leaks), and usual issues of down-sized pipes or missing discharge tube on relief valve (photo at above right)
Improper water heater exhaust venting, risk dangerous carbon monoxide leaks into the interior - see Carbon Monoxide - CO

MOBILE HOME PLUMBING Fixture Defects

Tubs: usual leaks at fittings; missing components,
history of leaks and no maintenance;
Fixtures or fixture drains damaged from freezing underneath the home in cold climates

Frequently Asked Questions (FAQs) about inspecting, installing or repairing plumbing systems in mobile homes, trailers, doublewides

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

[1] Section 184 Indian Home Loan Guarantee Program, U.S. Department of Housing & Urban Development, web search 1/5/2012, original source: portal.hud.gov/hudportal/HUD?src=/program_offices/public_indian_housing/ih/homeownership/184 - Quoting:
The Section 184 Indian Home Loan Guarantee Program is a home mortgage specifically designed for American Indian and Alaska Native families, Alaska Villages, Tribes, or Tribally Designated Housing Entities. Section 184 loans can be used, both on and off native lands, for new construction, rehabilitation, purchase of an existing home, or refinance.
Also see Freddie Mac & Fannie Mae
[2] Native American Housing Loan Guarantee Program HUD Section 184 Loans At A Glance, FannieMae, web search 1/5/12, original source: efanniemae.com/sf/mortgageproducts/pdf/section184aag.pdf
[3] Mobile Home Inspections - Daniel Friedman & Steven T. Vermilye
[4] Trailer vs Mobile Home vs Modular vs Panelized Construction an explanation of terms and how to identify these structures.
[5] "Modular Home Construction, special defects and inspection methods" Dan Friedman, NY Metro ASHI Seminar, Holiday Inn, Crowne Plaza, White Plains NY, October 4, 1996
[6] MOBILE HOME INSPECTIONS
[7] Trailer vs Mobile Home vs Modular vs Panelized Construction an explanation of terms and how to identify these structures.
[8] "Modular Home Construction, special defects and inspection methods" Dan Friedman, NY Metro ASHI Seminar, Holiday Inn, Crowne Plaza, White Plains NY, October 4, 1996
[9] New York State: "Manufactured Homes: an installation guide for the code enforcement official," undated. [Div. of Code Enforcement & Admin. - 518-474-4073, George E. Clark, Jr., Director] - this is a guide tool, not an enforcement code or standard.
[10] HUD State Administrative Agency (for 36 states) (NY: 518-474-4073) - for complaints
[11] Manufactured Housing Institute, 2101 Wilson Blvd. Ste. 610, Arlington VA 22201 703-558-0400 www.mfghome.org
[12] NYMHA, 35 Commerce Ave., Albany NY 12206-2015 518-435-9859 800-721-HOME (they want the Star Program to provide for separate assessment of manufactured homes)
[13] Consumer Reports: www.consumerreports.org - special report 2/98
[14] Mobile Home Inspection Checklist, Florida, Town of Lady Lake Building Department
[15] Thanks to home inspector Peter Bennett for eagle-eye editing assistance regarding spelling at this web article series. Little Silver, NJ 07739 Office 732-758-9887 Fax 732-758-8993 Cell 732-245-9817 afullhouseinspectionco@gmail.com
[16] Wikipedia provided background information about some topics discussed at this website provided this citation is also found in the same article along with a " retrieved on" date. NOTE: because Wikipedia entries are fluid and can be amended in real time, we cite the retrieval date of Wikipedia citations and we do not assert that the information found there is necessarily authoritative. - Entry on Mobile Homes, original source: http://en.wikipedia.org/wiki/Mobile_home#Regulation, retrieved 8/14/2012
ABS Plastic Drain/Waste/Vent (DWV) pipe failures: reported for Centaur, Phoenix, Polaris, Gable, and Spartan pipe mfgs. for pipe made betweeen 1985 and 1988. CPSC Hot Line: 800-638-8270 or ABS Drain Leaks/Failures-Class Action Settlement COX settlement through Shell Oil set up by a contractor involved in the settlementPolubutylene Plumbing Failures: Spencer Class settlement. 10% of replacement cost/damages, only for acetal (plastic)fittingsPolybutylene plumbing info at U. Arizona Polybutylene piping lawsuit settlement website Polybutylene plumbing lawsuit proposed settlement-old site
Polybutylene Plumbing Failures, Lots of Info about, but slow-loading busy site

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd

Crawl Space Moisture Control, U.S. Department of Energy
Domestic Building Surveys, Andrew R. Williams, Kindle book, Amazon.com
Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting:
A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
Moisture Control in Buildings, U.S. Department of Energy
Moisture Control in Walls, U.S. Department of Energy


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