FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

Water Heater installation surprises 40 gal electric.

fassbinder | Posted in General Discussion on July 12, 2012 07:04am

I’m trying to anticipate as many water heater installation surprises as I can. I haven’t called the building department yet because I want to know enough to ask the right questions.

Possible issues so far:

1. Drain pan. Found out it’s going to be required by code. Good idea.  A 22″ metal pan fits a 20″ dia WH right?

2.  Pressure Reduction Valve? Home Depot said this might be required if water pressure exceeded 80 psi (if I understood that correctly). Is there a way I can tell in advance if I will need this? Who would I ask? The Building Department, the local village water works?

3. Some videos I saw they were mentioning a metallic ‘bladder’ device that would prevent back ups into the public water supply. That’s a new one on me. Again, can I anticipate this? Who would (possibly) know in advance?

4. No earthquake straps required here.

I’m thinking I might be able to aquire most of these Big Ticket items ahead of time (if I know they’ll be needed) then hire a local plumber to put it in.

Permit required.

Any other ideas?

Thanks.

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. DanH | Jul 12, 2012 08:26am | #1

    First thing it to make sure that the damn thing will fit, physically.  Not usually a problem when the heater is installed in a open, full-height basement or garage, but if it's crammed into a utility room, under some ductwork, you may find (like we did) that there's only one or two models that can be used.

    Your local water company should be able to tell you what the common water pressure is in your area.  But if the area is quite hilly and you're near the bottom of a hill then you may want to simply go out and purchase a pressure gauge and fittings for a hose bib (if you can't borrow something from someone), to check for yourself.

    Re the "bladder device" you're confusing two related items.  If you have a pressure reduction valve, or if your locality requires a backflow preventer ("check") valve, then you need to get an expansion tank.  With the PRV or the check valve, when water heats it can't expand back into the main, so pressure in the house plumbing increases.  This would lead to frequent "popping" of the temperature/pressure relief valve on the water heater.  To prevent this, an "expansion tank" -- a roughly 1-gallon tank with an air-containing bladder inside -- needs to be installed.  It generally SHOULD NOT be installed on the hot water line or near the water heater, to prevent hot water from entering the tank and speeding the degradation of the bladder.

    Your local water company, or the building department, should be able to tell you if a check valve is required.  The check valve is supposed to prevent backflow from your system into the main, on the theory that this can cause contamination.  This would be highly unlikely under normal circumstances, but can occur when, eg, a fire truck hooks up on the next block and your water pressure drops below zero.  But be sure to not confuse the check valve that may be required on entry to the house with the one that is almost certainly required on any new hose bib -- the latter creates no problem for water heaters.

    (But note that, even though a PRV or check valve may not be "required", based on local conditons/rules, if you're working with existing plumbing one may still be in place, requiring an expansion tank.)

    1. fassbinder | Jul 12, 2012 08:54am | #2

      Thanks for the info.

      Was just reading the pdf of the WH manual. Clarifies things nicely.

      Found a unit same size diameter and actually 7 inches shorter so should be ok there.

      If I was the only person in the house I'd really like to take my time and learn how to do this myself.

      Given time I don't think it would be too difficult to work out the connections.

      The joint sweating would be the only thing I'd be hesitant about. Especially if those additional items would be required.

      At least I was able to replace a few faucets and toilet guts without calling in help.

      1. fassbinder | Jul 12, 2012 09:01am | #3

        I'm wondering I should elevate this with some 4" blocks. The pan would be sitting on top of the blocks. It sure would drain better.

        Might be overkill though as long as the pan would be there anyway.

  2. Tim | Jul 12, 2012 01:21pm | #4

    Ideas

    For the pan (I have never seen a Code that required one, but as you stated, a good idea), consider a plastic pan in lieu of galvanized.

    A plastic pan intended for a WH will have a provision for a drain. Will require a 3/4" bulkhead fitting and some piping to the nearest floor drain. Make use of that provision if you can.

    If you hire the plumber, pay them to install the necessary items that they supply (and guarantee). Otherwise, if you go get the Home Depot made in China backflow preventer (for example) and it doesn't work properly, the plumber will rightly take no responsibility.

    I am an avid DIYer. If I'm doing it, I would be doing what you are - finding out everything (hopefully) that I need and asking questions. IF I'm paying someone to do a job, I let them worry about all the details. In your case, relax and let your plumber do the job and pay them to do it right (but, hold them accountable to do so).

    While another poster covered the generic details, be very specific about a "backflow preventer". This is not simply a check valve (or an anti-siphon device, as was also described). It is a very specifc UL/NSF rated appliance. Typically, these items are not available at homecenter/box stores, but only at a wholesale plumbing supply. IF available, "Watts" is a recommended brand name to look for.

  3. [email protected] | Jul 12, 2012 02:35pm | #5

    ETC.

    The catch pan is required under current code, and must drain to somewhere, such that it prevents damage to the structure if the tank leaks.  Not sure that is always possible on retrofits. 

    The discharge pipe from the temperature/pressure relief valve, has to go to within 6-inches of the floor, cant reduce in size, shouldn't have more than 180-degrees of bends, and can't discharge to the catch pan.  Again, this isn't always possible.  It is also supposed to discharge where the occupants will notice it is disharging. 

    The PRV is typically required if the static pressure is above 70-psi.  They function as a backflow device, and if you install one you should intall an expansion tank.  I keep my pressure valve set down to 50-psi, and didn't install one.  The tank, and rest of the plumbing is rated for 100-psi, the water doesn't expand enough to get the pressure that high. 

    I doubt your existing system has any form of a backflow device.  The water purveyor can tell you if you need one. 

    The current code requires a mechanical disconnect within 5-feet of mechanical devices to isolate them from the energy source.  So on an elecrtric water heater, we have started to install breakers, or locakable switches next to them. 

    Typically water heaters are installed with flex lines, and no soldering is required.  Ideally there are isolation valves on both sides of the water heater.  With the preponderance of single handle faucets, it is nice to be able to close down both sides, so that if you leave the cold water on while you work, someone doesn't inadvertantly send water back down the hot side, from a faucet when they try to get a drink.  If your current setup is hard plumbed, and doesn't have isolation valves, have the plumber put them in.  That way you can do the work yourself next time. 

      

    1. Tim | Jul 16, 2012 04:07pm | #10

      Which code?

      You state "The catch pan is required under current code." Which Code? And what revision is current for you?

      It is not required by the applicable Code where I live and work.

      1. [email protected] | Jul 26, 2012 12:14pm | #11

        The International code.

        In the IRC it is P2801.5.

  4. user-1116010 | Jul 13, 2012 10:25am | #6

    water heater install preferences

    I prefer to use an aluminum or galvanized emergency drain pan, they are durable and sturdy, and hold up better than a plastic pan when the water heater is located in a high traffic area. A gravity drain connection is not always available for the pan's discharge pipe, so in these instances I recommend installing an automatic  shut off valve. This device works with a moisture sensing probe that is mounted in the drain pan; when the probe gets wet it sends a signal to a plunger type shut - off valve that is connected to the water heater's cold water inlet pipe. These devices are pre - wired and connect to a standard 120 volt electric outlet.  This valve can help prevent a catastrophic flood.

    A thermostatic tempering valve should be installed on all water heaters, and they  serve multiple purposes. Water heaters should be set to maintain a minimum temperature of 140 degrees F to prevent the growth of Legionella. Higher operating temperatures can add a little more capacity during peak demand periods when combined with a tempering valve. The tempering valve will deliver consistent, safe temperature water, and some tempering valves will even shut down  when the water temperature exceeds the set point.

    The water heater location is important for proper maintenance. Access and clearance are needed for yearly inspection of the anode rod. The safety relief valve should be exercised annully and flushing the heater via the drain cock can add years to the tank's life..............................MikeL

  5. fassbinder | Jul 13, 2012 11:58am | #7

    Actually was able to talk with a county Inspector.

    He mentioned that a metal drain pan is only required for new construction, not for a refit..but you're really stupid if you don't put one in if you ask me. Not much over $15 at Big Box.

    Also, in  the neighbouring (big city) county the expansion tank assembly is mandatory but not in this county. He wasn't aware of any special gizmos that are typically required in my area.

    Still not sure if I should elevate the WH and its 22" pan on 4" blocks or not.

    Lowes will install it for $259. Sounded good enough for me. It's a real drag shopping for plumbers, so I'm not going to bother. Their WH seemed to get better reviews over the Home Depot model.

    1. florida | Jul 13, 2012 04:18pm | #8

      What's the point in hiring a professional plumber if you're not going to use his expertise?  Any competent plumber would know the answers to all your questions and intall your water heater correctly.

      1. fassbinder | Jul 14, 2012 10:42am | #9

        Exactly.

        If the particular job requires no particular expertise there's no need.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Choosing a Paintbrush

Tips for picking the right paintbrush based on paint type, surface, and personal comfort.

Featured Video

SawStop's Portable Tablesaw is Bigger and Better Than Before

The 10-in. Jobsite Saw PRO has a wider table, a new dust-control port, and a more versatile fence, along with the same reliable safety mechanism included in all SawStop tablesaws.

Related Stories

  • Midcentury Home for a Modern Family
  • The New Old Colonial
  • Modern and Minimal in the Woods
  • Bryce Hollingsworth, Dry-Stone Waller

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 333 - August/September 2025
    • A Practical Perfect Wall
    • Landscape Lighting Essentials
    • Repairing a Modern Window Sash
  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data