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  • HEATING
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  • INTERIORS
  • PLUMBING
  • ROOFING
  • SEPTIC SYSTEMS
  • STRUCTURE
  • WATER SUPPLY
  • ENERGY SAVINGS
  • ENVIRONMENT
  • INDOOR AIR IAQ
  • INSULATION
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WATER HEATERS

AGE of WATER HEATERS
AIRBOUND HEAT SYSTEM REPAIRS
ALTERNATIVE HOT WATER SOURCES
ANODES & DIP TUBES on WATER HEATERS
ANTIFREEZE for BOILERS
ANTI SCALD VALVES
APPLIANCE EFFICIENCY RATINGS
AQUASTAT CONTROL Functions

BACKDRAFTING HEATING EQUIPMENT
BACKFLOW PREVENTER VALVE, HEATING SYS
BACKFLOW PREVENTER, HEATER WATER FEEDER
BACKUP HEAT for HEAT PUMPS
BLEVE EXPLOSIONS
BOILERS, HEATING

CARBON MONOXIDE - CO
CHECK VALVES, WATER SUPPLY
CHEMICAL CONTAMINANTS in WATER
CHIMNEY INSPECTION DIAGNOSIS REPAIR
CLOGGED DRAIN DIAGNOSIS & REPAIR
CLOGGED SUPPLY PIPING
CROSS CONNECTIONS, PLUMBING

DEBRIS in WATER SUPPLY, Water Heater
DRAIN a WATER HEATER TANK

ELECTRIC WATER HEATERS

FLOODED HEATING EQUIPMENT REPAIR
FLOODED WATER HEATER REPAIR
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB

GALVANIC SCALE & METAL CORROSION
GAS BURNER Flame & Noise Defects
GAS FIRED WATER HEATERS
GAS PIPING, VALVES, CONTROLS

HEAT TAPES, Heat, Insulation prevent Freeze-Up
HEATING COST FUEL & BTU Cost Table
HEATING COST SAVINGS METHODS
HEATING SYSTEMS

HOT WATER SUPPLY
HOT WATER IMPROVEMENTS
HOT WATER DELIVERY SPEED UP
HOT WATER EFFICIENCY IMPROVEMENT
HOT WATER PRESSURE EXPANSION RATE
HOT WATER PRESSURE LOSS
HOT WATER PROBLEM DIAGNOSIS
HOT WATER QUANTITY IMPROVEMENT
HYDROGEN SULFIDE GAS

INDIRECT FIRED WATER HEATERS

MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES

NO HEAT - NO HOT WATER: HEATER DIAGNOSIS
NOISE / SOUND DIAGNOSIS & CURE
NOISE CONTROL for HEATING SYSTEMS
NOISE, PLUMBING CHECKLIST
NOISE, WATER HEATER

ODORS GASES SMELLS, DIAGNOSIS & CURE
ODORS IN WATER

PIPING IN buildings, Clogs Leaks Types
PLASTIC HEATER VENT
PLUMBING FIXTURES, KITCHEN, BATH
PLUMBING VENT DEFECTS & NOISES
PUMPS, CIRCULATOR
PUMPS, HEAT PUMPS
PUMPS, OIL BURNER
PUMPS, PONY PUMPS
PUMPS, SEPTIC PUMPS
PUMPS, SEWAGE EJECTOR / GRINDER PUMPS
PUMPS, SUMP PUMPS
PUMPS, WATER PUMPS
PUMPS, WATER REPAIR

RANGE BOILERS
RELIEF VALVE LEAKS
RELIEF VALVES - TP Valves on Boilers
RELIEF VALVES - STEAM TP VALVES
RELIEF VALVES - Water Heaters
RELIEF VALVES - Water Tanks

SAFETY, HEATING INSPECTION
SCALE REMOVAL, WATER HEATERS
SEWER GAS ODORS
SOLAR HOT WATER HEATERS
SOOT on OIL FIRED HEATING EQUIPMENT
SPILL SWITCHES - Flue Gas Detection

TANKLESS COILS
TANKLESS WATER HEATERS
THERMOSTATS, HEATING / COOLING
THERMOSTATS, WATER HEATER
TIMERS for ELECTRIC WATER HEATERS

VALVES, PLUMBING

WATER CONTAMINANT LEVELS
WATER HAMMER NOISE DIAGNOSE & CURE
WATER HEATERS
WATER HEATER ALTERNATIVES
WATER HEATER ANODES, DIP TUBES
WATER HEATER AIR INLET
WATER HEATER DEBRIS FLUSH
WATER HEATER EFFICIENCY
WATER HEATER FLUSH PROCEDURE
WATER HEATER NOISES
WATER HEATER PROBLEM DIAGNOSIS
WATER HEATER PROPERTIES
WATER HEATER SCALE - De-Liming Procedure
WATER HEATER SCALE PREVENTION
WATER HEATER SAFETY
WATER HEATERS for HOME HEATING USE?
WATER ODORS, CAUSE CURE
WATER PIPES, Clogs Leaks Types
WATER PRESSURE & FLOW MEASUREMENT
WATER PRESSURE GAUGE ACCURACY
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PRESSURE REDUCER / REGULATOR
WATER PRESSURE PUMP REPAIR GUIDE
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER PUMP REPAIR GUIDE
WATER PURIFIERS
WATER QUALITY TESTS, CONTAMINANTS, TREATMENT
WATER QUANTITY IMPROVEMENT
WATER SOFTENERS & CONDITIONERS
WINTERIZE A BUILDING

More Information

Water heater drain (C) Daniel FriedmanHow to Drain a Water Heater - Photo Guide, Step by Step
     

  • Procedure for Safely Draining a Hot Water Tank
    • How to drain the water from a hot water heating tank
    • No Hot water? how to get more hot water flow, quantity, performance from your water heater
    • Guide to water tank draining procedure
  • Questions & Answers about how to drain a water heater tank
  • References

Click to Show or Hide Related Topics

  • WATER HEATERS - home
  • AGE of WATER HEATERS
  • ALTERNATIVE HOT WATER SOURCES
  • ANODES & DIP TUBES on WATER HEATERS
  • ANTI SCALD VALVES / MIXING VALVES
  • BLEVE EXPLOSIONS
  • DRAIN a WATER HEATER TANK
  • ELECTRIC WATER HEATERS
  • FLOODED WATER HEATER REPAIR
  • GAS FIRED WATER HEATERS & GAS HEATERS, HIGH EFFICIENCY
  • HOT WATER IMPROVEMENTS - home
  • HOT WATER DELIVERY SPEED UP
  • HOT WATER EFFICIENCY IMPROVEMENT
  • HOT WATER PRESSURE EXPANSION RATE
  • HOT WATER PRESSURE LOSS
  • HOT WATER PROBLEM DIAGNOSIS
  • HOT WATER QUANTITY IMPROVEMENT
  • HYDROGEN SULFIDE GAS
  • INDIRECT FIRED WATER HEATERS
  • NOISE, WATER HEATER
  • ODORS IN WATER
  • OIL FIRED WATER HEATERS
  • RANGE BOILERS
  • RELIEF VALVE LEAKS
  • RELIEF VALVES - Water Heaters
  • SCALE REMOVAL, WATER HEATERS & SCALE PREVENTION
  • SOLAR HOT WATER HEATERS
  • TANKLESS COILS
  • TANKLESS WATER HEATERS
  • THERMOSTATS, WATER HEATER
  • TIMERS for ELECTRIC WATER HEATERS
  • WATER HEATER AIR INLET
  • WATER HEATER DEBRIS FLUSH
  • WATER HEATER EFFICIENCY
  • WATER HEATER FLUSH PROCEDURE
  • WATER HEATER PROBLEM DIAGNOSIS
  • WATER HEATER PROPERTIES
  • WATER HEATER SAFETY
  • WATER HEATERS for HOME HEATING USE?
  • WINTERIZE A BUILDING
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Here we explain just how to drain the water out of a water heater tank. This step is a necessary first step for several water heater maintenance and repair procedures such as water heater flush-out, water heater scale removal, or replacement of the water heater pressure-temperature relief valve.

This series of water heater maintenance and repair articles describes how to inspect, operate, diagnose, and repair electric hot water heaters.

  • To drain your water heater tank, for example to replace a part, see WATER HEATER DRAIN PROCEDURE
  • To flush accumulated crud or debris from a water heater (yearly maintenance) see WATER HEATER FLUSH PROCEDURE
  • To de-scale or de-lime your hot water heater, see WATER HEATER SCALE - De-Liming Procedure
  • To diagnose and repair a bad water heater dip tube or anode, see WATER HEATER ANODES, DIP TUBES
  • To diagnose particulate debris in the building water supply, faucet strainers, etc. that comes from the hot water tank, and how to fix that problem, see WATER HEATER DEBRIS FLUSH

The articles at this website will answer most questions about water heaters as well as many other building plumbing system inspection or defect topics. This page contains links to in-depth articles on inspecting, testing, and repairing problems residential hot water heaters of all types, including their parts, controls, and alternative sources for hot water as well as tips for improving hot water temperature, hot water pressure, and hot water quantity.

Reproduction of this web page electronically at other websites is prohibited. If you cannot find information you need here or if you have comments, questions, suggestions for inspecting and diagnosing water heaters Contact Us

Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.

How to Drain a Hot Water Heater Tank

Question: Can I Drain My Water Heater Myself?

We have a gas water heater. I’m a rather handy man. Would it be possible for me to flush it myself? What is a typical cost for this kind of service? - K.S., Seattle

Reply: Sure, if you're handy and careful, it's not difficult and not many tools are needed. But

Watch out: it's easy if nothing goes wrong (we list some things that can go wrong here and at WATER HEATER DEBRIS FLUSH. And there are a few safety things to get right: avoiding being scalded, avoiding damaging a pressure/temperature relief valve, and avoiding flooding the home because of a snafu.

Water heater drain (C) Daniel FriedmanTips On Draining the Water Heater Tank: Don't try opening the hot water tank drain valve without first noting these warnings and tips:

  • The water heater heat source should be turned off and the water tank cooled down (or run hot water out through building fixtures) before attempting to drain the tank - there can be a serious scalding hazard otherwise. If someone turns on electrical power to an electric water heater that is empty, it is likely that the heater electrodes will burn up.
  • You can connect a garden hose to drain the water heater tank to a suitable destination.
  • Use a pony pump if you need to drain "uphill" from the hot water tank to a suitable drain location. See PUMPS, PONY PUMPS for details.
  • If it's a Sunday - you may have trouble obtaining spare parts or emergency plumbing service if a problem occurs
  • Be sure to have a spare garden hose cap to install over the end of the drain valve in case it drips and won't shut off completely
  • If you have trouble turning the water heater tank drain valve to open it - don't force it - if break off the valve stem you may have a leak that you cannot shut off except by turning off cold water supply to the water heater
  • After opening the heater drain valve, if you forgot to turn off the cold water supply coming into the water heater, you may find that water just shoots out of the drain forever - you'll need to turn off the cold water supply to the water heater.
  • You will probably need to open a nearby hot water tap to let air into the plumbing system and through it into the water heater tank so that water can drain out at the tank's bottom. We don't recommend opening the pressure/temperature relief valve for this purpose as you may find that the TP valve won't shut successfully afterwards. Details about letting air into the water tank so that water can drain out are at WATER HEATER AIR INLET.

More details about draining and cleaning or de-scaling a hot water tank, including the removal of mineral or lime deposits and silt, are provided at WATER HEATER NOISES where we describe water heater flushout and water heater scale removal.

If plastic water piping is installed, such as polybutylene water supply piping, it should be at least 18" from the water heater.

Water heater vacuum relief valves are required at water heaters in some communities, to protect against collapse of the water storage tank and to prevent backup of hot water into the cold water piping should cold water pressure drop. Here is Carson Dunlop's sketch of a vacuum relief valve.

What Goes Wrong When Draining the Water Heater Tank?

Watch out for these common problems that occur when you try to just drain a hot water heater tank:

Don't forget to turn off water coming into the water heater tank or you'll certainly never get it drained.

The water heater tank drain valve may be defective, may fail to open, or may fail to shut off, or worse, may break so that water comes blasting into the room where the heater is located. If this happens you will have to be able to turn off cold water coming into the water heater, and even so, water that is in the water heater tank and in building piping above the heater will drain backwards through the heater and onto the floor. Don't force any parts, especially parts on a plastic water heater drain valve.

Water heater tank drain valves are a pretty standard plumbing part. If your valve is worn or damaged, or if you just want to be extra safe, buy a replacement valve at a lumber or hardware supplier before starting your project. Most valves are standard 3/4" male pipe thread. You'll also need teflon tape or teflon pipe dope for the pipe threads.

The water heater cold water supply valve may not shut off: especially as that valve may not have been used for quite some time. Or you may not be able to turn the valve. Do not force the valve - you may break it. Sometimes we can loosen a recalcitrant water shutoff valve by a combination of a little squirt of WD-40 or a spray used by mechanics to free frozen nuts and bolts. Don't get these chemicals inside the water heater.

If your water heater supply valve won't turn off fully and is just dripping into the hot water tank, you can live with that during a water heater drain and repair project. If the valve won't turn off at all, you may have to turn off another supply valve upstream from the water tank, or possibly you'll need to turn off water supply to the whole building before starting your project.

If you run into trouble you won't want to have to leave the whole building water supply shut down, so having a few spare parts on hand to be able to close off the water heater itself (relief valve, tank drain valve) may be necessary.

The water heater relief valve may leak: often we use the test lever to allow air into the water heater tank during draining, as that will speed up the water heater tank drain process. But lifting the test lever can allow a bit of debris or even a damaged relief valve seat washer to flow out. At WATER HEATER DEBRIS FLUSH we discuss dealing with this problem.

Where should the water heater draining garden hose drain-to? If you are routing a water heater drain hose to an indoor floor drain, be sure that drain is not clogged before beginning the project. Try pouring a bucket of water into the drain. If you are routing the water heater drain hose to outdoors, the water leaving the water heater tank should empty far enough from the building that it won't leak back into the structure through the foundation wall. At WATER HEATER DEBRIS FLUSH we discuss dealing with this problem.


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Technical Reviewers & References

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

  • Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
  • John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: johncranor@verizon.net
  • Carson, Dunlop &
Associates Ltd., TorontoCarson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
    • Commercial Building Inspection Courses - protocol ASTM Standard E 2018-08 for Property Condition Assessments
    • Home Inspection Education Courses including home study & live classes at eleven colleges & universities.
    • Home Inspection Education Home Study Courses - ASHI@Home Training 10-course program.
      Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
    • The Home Reference Book, a reference & inspection report product for building owners & inspectors.
      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.
    • The Home Reference eBook, an electronic version for PCs, the iPad, iPhone, & 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.
    • The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors.
      Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
    • The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones.

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.
  • Home Reference Book - Carson DunlopThe 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.
  • Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
    Special Offer
    : Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
  • Carbon Monoxide Gas Toxicity, exposure limits, poisoning symptoms, and inspecting buildings for CO hazards
  • ...

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