what size pipe should be coming off the hot water tank I have & lousy pressure?

Question

I heard, start @ tank with 1/2'' then to 1/4 but for how far ???any one know??

Answer 1

I'm surprised at all these answers it took 6 tries to get to the point that it may not be pipe size at all but fact it could be getting clogged. Depending on the age of your house what materials was used. Lets say you have Galvanize pipe(no longer widely used in plumbing, and not approved by some local codes) this over time corrodes the inside, restricting water flow. If you do not drain your heater periodicaly, then this can cause sediments to flow through your pipe clogging filters and adding to the problem. Hardwater causes lots of issues, installing a water softner could help.
your question states what size pipe should be coming off the hotwater tank? 3/4" is the nipple size of hotwater heater, thats both inlet and outlet, and im not aware of it being smaller, you'd have to get a reducer to go smaller. Most homes go with the 3/4 supply then to 1/2" to the fixture valve, and from valve can go from 3/8" to 1/4".
if you have adjustable water pressure regulator you can adjust that, most are factory set at 45psi, and average home is 60psi. You can get booster, most tends to be noisy. If its all the faucets having bad pressure then could be your piping, especially if it happened over time. If it just recently started, check the lines, take off the aerator, remove the lines to the faucets, or it could be your cartidge.
other issues could be you have a leak somewhere between the meter and your home, reducing the pressure. sharing water with other people(apartment). check to see if the valves are open all the way, and it could be faulty/corroded valve. Tempory water loss such as opened fire hydrannt could be cause.

Answer 2

Most water lines enter at 3/4" and are kept that size until branching off for the rest of the house into 1/2" lines. Larger pipes increase volume, but pressure is increased in smaller diameters, its like putting your thumb over a hose.

Its probably not the size of the pipes. Is it hot and cold pressure, or only the hot water? If its only the hot it could be a valve is not fully open or is clogging with deposits. If its the whole house it could be a common valve, or if its always been low, it might be that your house is near the end of supply lines (the pressure to the house is just low). If that's the case, you can get a pressure boosting pump, not exactly cheap, but they work well.

Answer 3

I disagree with some of the information given. I made the mistake of installing a 1" PVC hot water line from the heater to the kitchen sink, A distance of 22'. The original line was 3/8" copper tubing. The new line is buried 24" deep under the dirt crawl space.

With the new 1" line, it takes almost 5 minutes for the hot water to get hot at the sink! All of that water in the 1" line must be replaced before the hot water gets there. What a waste of energy! Before I renovated the house and replaced the 3/8" line I thought was too small, I had plenty of hot water at that location. If you look under the sink at the size of the lines feeding the faucet, you will see that they are 1/4".

Of course there will be a certain amount of line loss, but the energy savings with the smaller line will balance out that loss.

Answer 4

Both the hot and cold lines on a standard water heater should be 3/4" By code you run 3/4" for 3 to 7 fixtures 3 fixtures and under 1/2" is OK so unless you have less than fixtures in your whole house you need 3/4" pipe

Answer 5

I use 3/4" for everything until the pipe makes the turn to go through the floor then I go to 1/2"

Answer 6

In 95% of my installations , I use 3/4" copper for both the cold and the hot side.If it more pressure you need, you should run both hot and cold 3/4" lines to the faucets that are farthest away then use 1/2"line to go up through the floor.

Answer 7

1/2" is as small as you want to go. I recommend leaving the water heater with 3/4" and reducing to 1/2" at each faucet take-off.

Answer 8

It could be from 3/4 inch to one inch, that's what I have, never 1/4 inch that way to small. You won't have any volume when More then one valve is open.

I have 3/4 to one inch and I can open all my lines and not see a drop in pressure, my well tank is 65 pounds I have all copper lines, I put it all in myself.