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Plumbing Water Feed

Star Using PEX to get potable water and hot water to your faucets and other fixtures.


Water line to house

This is the thick walled plastic pipe (designed for direct burial in soil) that comes from the wellhouse to the house.  It needs to be a nice big diameter to achieve good water flow.  I use 2" diameter pipe.

Main water shutoff

Having a main water shutoff as it enters the house is required by code.

It is a 2" diameter underground pipe to the house which then connects to a 2" PVC pipe inside the house. 

Pvc Pipe 2in  Details here .

Use a 2" PVC shutoff tap.

Pvc Ball Valve 2in  Details here .


It is worth noting the difference between PVC and CPVC.  PVC is the regular white pipe and should be used with PVC fittings.  CPVC can handle hot water better than PVC, but PVC is fine up to 140 degrees F.  The water supply to the house is cold water and as such it is best to use PVC pipe and fittings.

It is ok to use regular white PVC pipe and fittings for cold potable drinking water.

If you are handling hot water then you need to use CPVC pipe and fittings.

NSF certified

NSF is a Public Health and Safety Organization.  Amongst other things, they certify that products are safe for potable water.  It is always good to choose products that are NSF certified when plumbing potable water.  There is useful info at http://www.milwaukeevalve.com/data/pdf/NSFandMV.pdf .

Water softener

I don't use a water softener as I don't have hard water.  If I did have one it would go after the whole house water shutoff.  Softened water is nice to bathe in and good for keeping the shower and tub clean.  Even if not installing a water softener it is good to provide space for it and a length of 2" PVC pipe that can be cut to add it later.

Toilet flushing water distribution

This is a dead-headed feed that goes past all the toilets in the house in a daisy chain with taps off to the different toilets.  The pipe is 2" PVC past the basement toilets and then changes to 3/4" PEX for the upper level toilets.

A deliberate pipe disconnect/reconnect changeover is provided so the toilets can be switched between potable water or pressurized rain water.  A 2" PVC check valve is provided so no water from dirty pipes ever flows back into the potable water system if rain water has ever been used.

Fire sprinkler water distribution




Cold water distribution (unfiltered)

It is good to avoid water going stale in the cold water pipes.  This is a particular problem in a large house with any faucets that are rarely used.  Rather than using a central manifold with pipes star-ed out to each faucet, it is better to use a loop that goes around the house past each faucet.  The source water is applied to both ends of the PEX loop and it practice the water will run in whatever direction provides the least resistance.  It is good to arrange for a high usage faucet to be at the farthest point in the loop.

Fixtures such as baths, showers, washing machines, etc are best fed with unfiltered water.  This is partly because there is no point in wearing out a filter with all this water and partly because you want the maximum possible flow.


It is best to connect water from a star point to the various plumbing fixtures.  The connections to the fixtures is best done with 1/2" PEX pipe.  A manifold is needed to convert the 2" main water feed to the numerous 1/2" PEX pipes.  It is also good to provide a shutoff tap on each of the separate 1/2" PEX feeds.

This first manifold is used to provide the feeds of unfiltered water. 

This manifold is used for the unfiltered basement fixtures and for providing the feed to the filtered manifold.  The 2" pipe continues up to the upper floors that have their own unfiltered cold water manifolds.  It is nice to have separate manifolds on separate floors as it reduces the 1/2" PEX run lengths and also is close to the fixtures if the water supply needs to be quickly turned off to a fixture that develops a fault.

You can use off the shelf manifolds but I prefer to make my own manifold because it provides less restriction to water flow, less interaction between fixtures, is more flexible in the number of provided feeds, is more flexible in the physical placement of the feeds, and is less expensive.

Use 2" PVC pipe as the main trunk feed, then 2"x2"x1" Tees to make 1" sub lines, then 1"x1"x3/4" Tees to make the individual feeds.  3/4" PVC goes into 3/4" shutoff valves and then finally use a 3/4" MNPT to 1/2" PEX converter.

Pvc Ball Valve 3-4in  Details here .

Water distribution to toilets

This is done with 2" white PVC pipe.  It is the same 2" pipe that feeds the unfiltered cold water manifolds on the upper floors.

Pvc Pipe 2in  Details here .

It is best to route the pipes via the attic and back down to allow for the future possibility of using rain water from an attic tank for toilet flushing.

Cold water to hot water heater

It is worth using good diameter pipe to the hot water heater so as to not reduce the flow.  Near the water heater, the pipe needs to be approved for hot water even on the cold water intake.  I use 1" PEX from the unfiltered cold water manifold to the water heater.  There is some question about using PEX to connect to water heaters, but I think it's fine.


Water filter

A water filter is worthwhile, but I'm not convinced it's worth spending the money on a mega expensive one.  I used a $50 water filter.

Water filter Omni U25   Details here .

For really clean water it is good to put a Reverse Osmosis Water Filter under the kitchen sink, particularly as these are now under $200.

Reverse Osmosis Water Filter With Faucet

Whole house Filtered Cold Water Manifold

This manifold provides the feeds of filtered water to faucets on all the floors that want drinking water.  There is no point in using 2" PVC pipe as the input to this manifold because the flow rate is already limited by the water filter.  Using 1" pipe is fine.

PEX for cold and hot water


For potable (ie drinking) water you need PEX tubing that DOES NOT have an oxygen barrier.  The type with an oxygen barrier is just for use in radiant heating systems where the heating system uses cast iron parts and you want to avoid rust.  If you are certain you will never have cast iron components in your heating system then you can use NON-oxygen-barrier for the radiant heating system too.  My advice is to just avoid using cast iron, ie use NON-OB PEX everywhere.

Typically use 1/2" PEX to the various fixtures.  Where you need high flow of cold water, eg to toilet flush-o-matics then use white PVC pipe.

The best brand is AquaPEX.  The best type is PEX-a.  AquaPEX is the only PEX-a material available for drinking water.  Details are here .

PEX pipe blue half inchPEX pipe red half inch

Connection system

There are various connector types that can be used with PEX tubing, but here is my recommendation.  Use the crimp connectors/fittings, but use them with stainless steel clamp rings (rather than copper crimp rings).  Crimp style fittings are the most common and affordable type of PEX fittings and can be found in most home centers and online stores.   It will cost you about $70 for a clamp tool (but this is less than a crimp tool).

PEX Crimp Tool

Pex Crimp Ring Half Inch

The clamping system is just like the crimping system but has the following advantages:

Tool fits into tighter spaces
Less accuracy is required
The tool is slightly cheaper
Less prone to operator error

PEX crimp connector - angled   Details here .

I prefer to use plastic connectors as there is no possibility of them containing lead.  If you do buy any brass fittings then make sure they are zero-lead.

Lots of extra good info on PEX is available at http://www.pexsupply.com/resources .

Little known handling characteristics of PEX

All PEX tubing not totally concealed in the wall cavity MUST BE sleeved with a UV light barrier sleeve.

PEX may not be connected directly to a water heater.

PEX tubing may not be run within 6" horizontal or 12" vertical of a water heater or furnace flue pipe, a heating unit or a fluorescent or incandescent lighting fixture.

Horizontal runs of PEX tubing must be supported at not more than 32" increments..

On a horizontal run, PEX support hangers must not restrict movement of the tubing.

On a vertical run, PEX must be supported at each floor plus halfway between floors.

When running PEX, you must allow 1" per 100 linear feet for each 10deg.F change in working temperature differential.

The minimum turning radius of PEX may not be less than 5x the tubing diameter (some local codes restrict it to 8 or 10 times the diameter).

When bending PEX tubing it may not be bent contrary to the natural curl of the tubing from the original roll.

PEX tubing must be stored and transported in a closed shipping container and should only be opened immediately before use.

PEX tubing must be cut with a plastic tubing cutter.  If a hacksaw is used, the tubing must be supported in a miter box while cutting.

All fittings used on PEX tubing must be specifically listed in the manufacturers data sheet as being acceptable for that particular brand of PEX tubing, and the manufacturers data sheet must be on the jobsite during installation.

When installing PEX tubing it may not be dragged over bare earth or a concrete surface.


Water heaters

Avoid anything that has cast iron because it will rust if you use the water for radiant heating and you use potable water PEX tubing.

Avoid a tankless water heater (unless you live alone in a one room apartment that has poor insulation and you are out all day).  A water heater with a well insulated tank will give you better efficiency and the small amount of heat that does escape will be within the thermal envelope of the house so will help warm the house.

The latest building code requires the use of a heat pump water heater because of its greater efficiency.

In the case of a resistance water heater, site the boiler where the small amount of escaping heat can be the most beneficial.  A good place is in an airing cupboard for clothes on the bedroom floor, although in practice it is more practical to put it in the basement.

Water heaters with tanks come in a full range of sizes from a few gallons (the one pictured is 6 gallons and is not a heat pump type) to many 10s of gallons.

Small water heater 

Water leaks and floor drains

Safe pans are required by code under water tanks six gallons in capacity or more when elevated above any occupied space, minimum drain size is 1-1/4”.  (A safe pan or safe waste system is not required by code under washing machines.)   In my case the water heater is in the basement, ie not above an occupied living space, so a water catching pan is not required by code.

A safe pan under a piece of equipment is for emergency purposes only.  When not an emergency it will always be dry (and so a trap would be dry).  The drain from the pan must be tied indirectly (via an air gap) to an active fixture like a utility sink.

Under a water heater you do ideally want to have a mechanism for catching water if it leaks.  You don't want a floor drain in the basement slab so you need another mechanism.  I use a raised floor with waterproof membrane to form essentially a shower tray.  There is a 1.5" drain in that waterproof raised floor that goes via a 1.5" ABS pipe to above the mud-room utility sink.

Hot water manifold

I chose to have just one hot water manifold for the whole house and to site it in the basement ceiling above the hot water heater.  The is no fixture than needs more flow than can be handled by a 1/2" PEX feed.  I made my own manifold using a 1" CPVC trunk with 3/4" CPVC valves.  Note the need for CPVC rather than PVC.

CPVC Shutoff 34 in   Details here .

Hot water pipes inside the house should ideally be insulated so hot stays hot and you don't waste energy (in summer).

Pipe Insulation Half Inch   Details here .


Separate drinking water system

Many people will consider this to be unnecessary, but I am very fussy about my drinking water.  The main water feed to the house from the WellHouse is perfectly drinkable, but there are big holding tanks and big umps involved.  I like the water best when it is fresh out of the ground, ie has had no opportunity to get stale in a big reservoir tank.  I have chosen to implement a separate small volume water system that feeds the drinking water via a half inch PEX pipe to the house.  It feeds a dedicated faucet in the kitchen and three on the bedroom floor (in bathrooms) using a simple daisy chain.  Details of what's needed in the WellHouse to feed the PEX pipe are here .