Low boy water heater leaks at point where cold water pipe enters caseing.The leak is below the threads.The caseing is rusted at the point where the pipe goes through.Can this rusted place be patched or sealed,and if so,where would the water go.

Hi -

If your water heater is working (ie: making hot water) then most likely your heater isn't leaking. Rather, the leak is coming from the cold water supply and running down the tank where you see it at the bottom of the tank. A working tank that is leaking would produce a leak of hot water - not cold. You should carefully check the cold water piping for a leak, drip or stream of water and make the required repairs.

Are you installing nipple in top of tank-type water heater?
Did you use 6 wraps teflon tape?
Is the nipple IP iron pipe tapered thread? Or is it straight thread?

Why are you replacing nipple?
Was old nipple leaking?
If previously sealed pipe connection to water heater has started leaking, then it implies the tank is rusted, and water heater needs to be replaced.
http://waterheatertimer.org/Leaking-water-heater.html

Have you checked the anode rod.
http://waterheatertimer.org/Replace-anode-rod.html

Why are you using brass instead of pex-lined di-electric nipple, available from box store?
http://waterheatertimer.org/images/IMG_1879-di-electric-nipple-800.jpg

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

If your unit is leaking from the joint where the pipe actually meets the tank, the only solution is to remove the pipe, check the threads to make sure they aren't all beat up and scratched badly, then re-wrap with teflon tape clockwise while you're looking at the pipe's open end. Three wraps is usually sufficient,, then re-insert into the threads and tighten with a medium pipe wrench. Tighten until you can't turn the pipe any more.

The warranty should not be void by using water softener, BUT read product manual.
http://waterheatertimer.org/Water-heater-manufacturers.html

1) First thing: Why is water heater leaking? Where is the leak?
http://waterheatertimer.org/Leaking-water-heater.html
For example, if you have electric water heater leaking from element, then replace element.
Replace leaking TP valve.
If water is leaking down vent pipe, and combustion chamber rusted out, then vent problem must be corrected.
These are not covered by warranty.
If tank is rusted out, then read below.

2) If water heater is rusted out after 4 years, you might have stray current corrosion.
This happens when hot and cold pipes are not connected together with a ground wire, and/or if cold water pipe is not grounded to earth.
This might not be covered by warranty.

3) Read water heater instruction manual for advisories.
Tanks rust out when anode rod is depleted. Softened water depletes anode rod faster.
Instruction manual says to check anode rod each year.
Checking anode rod is like checking oil on an engine. If oil was never checked and engine burned up, the manufacturer will not honor the warranty.
If anode rod is depleted, and tank is rusted out, the warranty might not cover the rusted tank since owner was supposed to check for anode depletion.

4) Anode rods can also be covered with calcium deposits and stop working.
This night not have anything to do with water softener, but anode stops working and tanks rusts out.
In any case the owner's manual probably says to check anode rod to prevent leaking from rusted tank
http://waterheatertimer.org/Replace-anode-rod.html

If tank is rusted out, then that is caused by depleted anode rod, or tank that is not electrically grounded on hot side pipe.
If pipe nipple is rusted out, then that can be caused by improper connection between copper and galvanized pipes, and caused by non-grounded hot water pipes.

If tank is leaking, replace it.
If nipple is leaking, remove with pipe wrench, apply teflon tape or joint compound on threads, and install new nipple. Replace anode rod if possible. Correct copper-galvanized connections. Add ground wire between hot and cold pipes.

http://waterheatertimer.org/Leaking-water-heater.html
http://waterheatertimer.org/Replace-anode-rod.html

Your tank is rusted out and needs to be replaced.
Link below is a troubleshoot for leaking water heater.
http://waterheatertimer.org/Leaking-water-heater.html

Protect yourself first:
If your tank is rusted, there is danger of rupture.
My friend welded his leaking tank, but he assumes the risk.
Ruptured tank can cause massive damage and water runs until it is shut off.

Hot water tank is under pressure because hot water expands and pushes against tank wall.
Turn off water to tank.
Turn off power supply:
Electric: turn off circuit breaker.
Gas: rotate knob to pilot so pilot stays lit but burner will not fire. To turn back on, rotate knob to ON.
Open hot side bathtub valve and relieve pressure on tank.

You can limp by with rusted tank by turning water heater on when hot water is needed.
Shower uses 5-9 gallons hot water
Bath uses 12-15 gallon hot water
Ordinary gas heater makes 41 gallons hot water per hour
Ordinary electric heater makes 20 gallons hot water per hour.

I buy water heaters at Lowes, Home Depot, Ace.
Look for scratch and dent models.
Buy drip pan for water heater.
Wrap electric heater totally with insulation except TP valve.
Buy new flexible connectors for water lines.
Offer 15% less than marked price on tank, because the store makes money on additional items.

> Most people can install their own electric heater since you just connect water pipes and electric wire, and it's done. Read link below since there are tips that help you buy and install electric.
> Generally people are nervous about installing gas water heater, so step-by-step instructions are shown on link below. Remember gas line is under less pressure than water line, so if you can install a water pipe, you can install gas line to water heater with crescent wrench, and soapy water to check for leaks.
How to install gas water heater:
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, fixya expert speaks with you over phone while you work on water heater, or any do-it-yourself project.

If you have a leaking water heater there is a serious problem.
http://waterheatertimer.org/Water-heater-leaking.html
Page shows how to limp along on a leaking water heater if your water heater needs replacement.

One of three things is causing the water:
1) Loose water connection on top of tank that is dripping down inside tank >> check pipes on top of tank.

2) The vent is clogged or not working correctly causing condensation inside flue pipe.
Condensation water is dripping back down inside tank.
Problem means possible CO poisoning if gas is not venting.
Look at vent pipe to see if joints are corroded.
Use long fireplace match > light match and put into draft hood at top of tank and see if smoke goes up.
Put hand at draft hood opening when water heater turns on to see if vent gas enters home.
Do same test when furnace turns on to see if furnace vent is pushing back into water heater.
Does water heater vent inside same pipe as furnace? You may need to set up separate vent for water heater if furnace gasses are pushing back into home.
Check furnace vent for obstructions.
Look at vent stack top of home to see if hood is in place.
Check if bird nest is built inside warm vent pipe.
Improper flue is top priority for getting fixed so vent gasses properly escape home.
You may have to call a plumber.
Professional plumbing forum:
http://www.thetankatwaterheaterrescue.com/forums/forum3/

3) Your water heater is rusted out.
A rusted tank has to be replaced.
It cannot be repaired.
However, before replacing tank, you do not want a tank failure where tank ruptures and water runs inside home until water is shut off.
This will cause major damage.
Protect yourself first.
Turn off water valve above tank.
Move gas knob to 'pilot' so burner is not heating water.
Open tub spout on hot side to relieve pressure on tank so it will not rupture.

Now you're protected.
Link above shows how to limp along on failed tank until you can replace heater.

You need a new gas water heater from Lowes or Home Depot
Look at label on side of you tank for gallons and btu's of your water heater.
Measure height to flue pipe so you get same height water heater, so pipes don't have to be changed.
You need a pipe wrench and teflon tape which will be wrapped on each pipe thread when pipes are reassembled.

Step1) Drain water heater using valve at bottom of tank.
http://waterheatertimer.org/Water-heater-will-not-drain.html

2) Turn off gas valve going into heater.
When gas valve is perpendicular to gas line, then gas is off.
Dissemble gas line to water heater.

3) Disconnect flue pipe and support flue pipe with wire so it doesn't not fall down. Flue pipe joints should be held together at each joint with 3 screws.

4) Turn off water. Shut off valve is on COLD side.
Disconnect water pipes.

5) Move old water heater out of way.

6) Set new water heater in place. Put water heater in drip pan.

7) Connect water pipes >> cold goes to side marked cold.
Hot to hot.
Buy new flexible water connector pipes at home center for easy installation of water pipes.

8) Connect gas line exactly as it was connected before.
Home center sells flexible gas line connector for easy installation of gas line.
To test for gas leak after installation, mix liquid soap with water and put around gas line joints to see if there are bubbles.
Natural gas has less pressure than water lines, so gas pipes are easy to seal with ordinary wrench.

9) install TP pipe that runs to floor. Use old one off old heater.

10) Fill tank completely with water until water is coming out of tub spout.

11) Turn on gas, and light pilot as shown in manual.
New gas heater sometimes have small water leak when first fired up, so ignore a bit of water.

12) Save water heater manual like it is gold, and read everything in manual.

It sounds like you need to replace it, Actual cost can very widrly depending on your location but I would say $350-400 is probably close. Plus installation unless you can do it yourself. Hope this helps. Thanks

It sounds like two problems.
Problem 1) Clog inside faucet or clog inside pipes at faucet
Remove supply tubes leading to faucet and see if problem is inside pipes or inside faucet.
My bet is clog inside faucet.

If you have galvanized pipe that meets copper pipe, this can be trouble spot.
Article on clogged water pipes at Inspectapedia:
http://www.inspectapedia.com/water/Water_Pipe_Clog_Repair_Guide.htm

Article on clogged pipes:
http://www.waterheaterrescue.com/pages/WHRpages/English/Troubleshooting/Tanklets/backflushing.html

Problem 2) Water heater leak ... you say tank valve is leaking? Is that cold-water shut-off valve? Or tank drain valve? Or TP valve?

If cold water shut-off is leaking, then replace shut off.

If tank drain valve is leaking, then check if plastic valve is cracked. If drain valve is cracked, then replace with a brass valve from Home Depot. If plastic valve breaks off, then use hammer and screwdriver to gently chip out the broken plastic valve. New valve threads need teflon tape to seal pipe. If valve is just dripping, then put garden-hose cap over end of valve and screw down tight.

If TP valve is leaking, then replace with same temperature and pressure rating. New TP valve threads need teflon tape to seal pipe.

Problem 3) If pressure is low all over house:
Buy pressure gauge at hardware store that screws onto hose connection.

Test pressure on outdoor spigot.
Open faucet and check if pressure drops. This says if problem is inside pipes that enter house.

Test pressure on water heater drain valve.
This says if pressure problem is before -or- after water heater.

If problem is before the water heater, then shut-off valve located on cold water line is suspect.
If problem is after water heater, it could be in hot water outflow pipe on top of water heater, or a nearby elbow.
Remove hot water line leading from water heater and check pressure. This says if problem is where hot water leaves tank.
Read articles above about clogs inside water lines.

What is the leaking pvc pipe connected to? The T & P valve on the side (or top) of the tank? Or is it an incoming cold or outgoing hot water line? If you have just lit the water heater, the T & P valve may drip, but only for a little while and it will stop. The T & P (temperature and pressure relief) valve may be bad and need replaced. Turn off the incoming cold water valve and turn the gas valve to off position. Then drain the water heater using the T & P valve, it will stop draining when the water level is just below it. Remove the T&P valve and replace with new one. Use thread sealing tape on threads. Or call a plumber if not sure.