Does a water well need a vent on the cap?
My wall has a weird cap because it once had as an old fashioned
windmill setup. There is just one small hole, and the wires come out
of there. It does allow venting around the wires, even if that is a
small amount. The problem is that rain water can enter from that
hole. I've always kept an upside down pail on it to prevent water and
bugs from entering. We're doing some work to this well and a guy told
me to just out silicone around the wires. I know that will seal the
hole, but dont the well need some venting to allow air to displace the
water that is pumped out? It would seem to me that not having a vent
would make the pump work extra hard, and create a vacuum in the well,
which might cause other problems.
Or, does the water entering the well make up for the water removed?
The well is plenty high. About 2 feet exposed casing and on a mound.
It's just rain water that can get in. The rain water in itself is
probably not bad, it's the dust and dirt the is on the cap, and water
dripping off trees and such, that goes in with it that is the problem.
Not to mention bugs.
As to another reply, the well is 300ft. deep, the pump is at about 280
to 285 ft. down.
On 11/23/2011 1:00 AM, firstname.lastname@example.org wrote:
All wells need an air vent. Not because of water, but because of air
pressure changes. Your air pressure is always changing. Check your daily
weather report and notice the change in barometric pressure.
Your well is probably not very deep. My well is drilled to 650 ft. The
water is down perhaps 500-550 feet. that is a lot of air space. The well
cap allows air in and out of the well. Many times you can hear it
whistling. Sealing the well would eventually create a vacuum and make
the pump work much harder to get the water up and out of the well.
My well has a small, well insulated building over the well. It is well
insulated because it needs an electric heater to keep the outgoing water
line from freezing.
Here is what happens when the winter air here gets to -15. That occurs
usually when a high pressure system passes over Central Oregon. The high
pressure forces the -15 degree air through the vent in the well where
the air expands, cooling the already frigid air to way below -15
degrees. This cold air causes the water in the pipe at the well top to
When the water in the pressure tank goes down, the pressure switch tells
the pump to pump. It pumps against the frozen water in the line, but no
water gets to the pressure tank. So the pump just runs and runs and the
house still has no water. Eventually the pump burns out and you are screwed.
This happened to the previous owner. So he kept an electric heater in
the well house. I do the same. One winter, I set the heater control too
low and it never turned on. When the house water stopped one really cold
day, I knew exactly what was wrong. I turned off the pump and turned up
the heater control and then tried the pump about once an hour. Finally
the warmed air in the pump house going down the well vent hole thawed
the frozen pipe and all was working again. Whew!!!!
When your well had a windmill, and if it ran in the winter, a frozen
pipe would either break the pump or force water back past the leather
packing in the pump. Either is not good. I suspect the windmill was not
used in the cold of the winter.
I agree. That air is barely moving and going through a pipe
intended to support free flow, not create a pressure differential like
an orifice in an HVAC coil.
Any change in temp is going to be very small. I can see
the pipe freezing near the top of the well head just from
the cold -15 air though, without additional cooling.
I think the main issue today with having a well vent is to
eliminate any negative pressure in the well. If you have
negative pressure, it would make any small leaks worse
that could possibly result in ground water getting in around
a seal, etc. How much of an issue it really is, who knows.
The OP could check with his local code office or try googling
for his state info which might be online.
Yes, wells do need a vent. The vent should not allow surface water to
enter the well. The quote below is from:
An approved well cap or seal shall be installed at the top of the well
casing to prevent any contamination from entering the well at the surface. A
well vent is required. The well vent pipe shall be at least ½ inch in
diameter, 8 inches above the finished grade, and be turned down, with the
opening screened with a minimum 24-mesh durable screen to prevent entry of
insects. Only approved well casing material meeting the requirements of the
IWWCC may be utilized. To prevent contamination, the annular space between
the drill hole and the well casing shall be grouted below the pitless
adapter or unit in accordance with the IWWCC.
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