I am installing the supply lines in new construction (building my own house from the ground up and now doing the supply lines)

I have a well and pump with 1 inch supply line into the house and an 80 gallon pressure tank. That goes to a 50 gallon water heater with 3/4 inch outlets.

To increase water pressure on the hot water side can I increase the supply line back to 1 inch after it leaves the 3/4 inch hot water heater outlet?

I would then decrease it back to 3/4 inch and 1/2 inch as it reaches individual fixtures. It is a large house (7 baths) so I am concerned about the pressure. I know I can decrease pipe size as I go along - but can it increase to 1 inch coming out of the water heater?

You are confusing pressure with volume. The pressure through out you system will always be the same. What that pressure is, depends on what pressure you set you pump switch to.

You can have a 1' pipe with a certain pressure and get a certain volume (GPM).
You could have a 6' pipe with a section of 1" pipe and get the same volume. The volume being restricted by the smallest diameter pipe it must pass thru.
Note that the supply lines of most faucets are 1/4". Tub and shower faucets are piped with 1/2" piping.
There is a certain number of different type appliances that can be supplied by a certain size piping. Unfortunately I don't know the code. Maybe Mark (Massplumber) will come along. Hose bibs have the largest volume, then tub faucets, kitchen faucets and then lavatory faucets.
Note that a 1/2" pipe is four times larger than 1/4", 3/4" is two times larger than 1/2" and 1" is 1.75 larger than 3/4".

You have a well and pump. The pump can deliver a certain amount of water at certain pressure, depending on the pump size and the depth of the well. The volume of water you have available at any given time is the volume stored in the tank (about 1/3 its stated size) and the amount of water that the pump can pump once the pressure drops to the cut on setting.

A well pump with 1" well piping and 1' piping from well head to tank will recover faster that 3/4" piping.

Just how you size you piping will depend o the physical lay out of the bathrooms. Increasing and then reducing pipe size won't do anything for you.

As far as I know all domestic water heater have 3/4 fittings. Increasing pipe size won't increase volume. With 7 bath you certainly will want multiple water heaters, probably piped in parallel with recirculation lines if they are located at the same place. If you locate them close to the points of use you won't need the recirculation lines.

Sounds like you need a plumber to lay out the plumbing for you. If you anticipate multiple showers being used at the same time I hope you have a high volume well and pump.

Harold (hkstroud) covered this very well... so you now understand the difference between pressure and volume.

Are you planning on having a Jacuzzi, a whirlpool, or a soaking tub in any of these bathrooms? If so, then that 50 gallon water heater may not be enough. In this case, you may want to look at a commercial size water heater (1" tappings) or you may want to install multiple tankless water heaters or 2-50 gallon water heaters. If you are thinking about installing showers with multiple heads, you'll need to purchase 3/4" shower valve bodies and run 3/4" to these shower valves. If you plan on running multiple bathrooms at the same time, this gets even a little more complicated...1" may simply not have enough volume to adequately supply all the fixtures you want to run at the same time.

Recirculation lines, as mentioned by Harold will be critical in this house, especially with any bathrooms over 75 feet from the water heating source... please be sure to investigate this further.

We are glad to continue to discuss this with you, but you may be better off consulting with a local plumber and having him do a water distribution chart showing exact size/pressure/volume required by code for this house.

Back to you...

Mark

Hi Mark,

Back from the Bahamas I see.

Wife get good tan? Lots of lobster and martinis I guess.

No problems with the yacht I hope.