Dan Espen wrote:
hubops writes:

So, what about that PEX pipe? How does that hold up in sunlight?

Normal PEX is not UV resistant.
There exists specialty PEX that, apparently, is
http://www.seymour-ind.ca/displayProduct48.php
Why not just use an old garden hose ?
John T.

Why not use a garden hose???
Well, the last hose I bought had a warning on it not to drink
from it. It said the hose leaches toxic agents into
the water.
Normally I discount these kinds of warnings as some company
trying to avoid a lawsuit but Google seems to confirm.

Garden type water hose is color coded to indicate potability,
typically white or blue but each manufactures has their own coding
(check their web site). I'd not use non potable water hoses for live
stock, and as hose ages more and more toxins leach out.

Perhaps real underground water pipe is the best answer.

That's what I'd use, irrigation tubing is very inexpensive and it's
non toxic. Just this past summer I had my vegetable garden irrigation
well re-plumbed with a new self-draining pressure tank fitted. I
don't use that well in winter so I don't heat the room containing the
pressure tank, I shut it down and all the water drains back down into
the well so no freeze ups. The run from the well to the well shed
coincidently happens to be forty feet, that line is buried past the
freeze line which is five feet here. The water line is 3/4" poly
irrigation tubing encased in 4" PVC... done so in case the poly
springs a leak it would be easy to replace without digging. In this
farming community well water used for livestock is regularly inspected
for toxins and microbes by the health department. If that water is
for horses I strongly recommend a professional installation, not some
mickey mouse DIY old garden hose.
Trench being dug to well:
http://i66.tinypic.com/mcsrxj.jpg
Laying in the water line, notice the level to check that it pitches
back to the well:
http://i67.tinypic.com/23r4b49.jpg
Nicely graded with lots of added topsoil and grass seed planted:
http://i66.tinypic.com/alr9jb.jpg
New self draining pressure tank supplies a hose bib for watering my
garden, etc:
http://i65.tinypic.com/rmis81.jpg
That's a a very good well, supplies nearly 20 GPM, twice what my house
well supplies. Living with well water for most of my life I've
learned a lot about wells and piping water. An ordinary garden hose
is fine for watering a lawn, a pumpkin patch, and washing a car, but
not for watering valuable livestock. Many people drink water raw from
their tap and then 20-30 years later die from cancers... mine goes
through an RO filter and is treated with a UV lamp... even my feral
cats are watered with RO water. Those in-line filters people use at
their kitchen tap are worse than fish tank filters, they remove little
more than odor and add lots of bacteria/viruses... anyone who drinks
water from those paper filter elements for months between changes
changes their underware no more often.
Anyway I have trouble imagining someone who keeps horses can't afford
to water them properly, horses are very expensive to maintain,
watering is the least of it... I live in horse country, famous race
horses are raised, bred, and stabled here. Most every teenage girl
owns a horse, I know very well what it costs to keep horses, my
daughter had a horse here from six years old until she married and
moved. I lived near this hupoops miser I'd definitely report him to
the authorities for animal abuse.