Thursday, April 17, 2014

Water Table

Yesterday a reader left this question in the comments section: " Any insights into ground water on Ocracoke? Clearly it would vary by location/elevation, but in the area of the Village Craftsmen, for instance, how far down can you dig before you hit ground water?"

In 2008 Lou Ann wrote a humorous article about me installing a pitcher pump behind my house. The article will illustrate what it takes to tap into island ground water. You can read that article here:

At the end of the article I added this geology note:

Ocracoke, like the rest of the Outer Banks, is low and narrow.  As rain falls on these barrier islands water filters through the sandy soil. What does not run off into the Atlantic Ocean or Pamlico Sound flows below the surface where it mingles with underlying sediments that are saturated with salty ocean water. Although some intermixing occurs, fresh water is less dense than salt water, and forms a floating lens above the salt-laden water.

The boundary between the fresh and salt water layers varies with the tides and rainfall, but Ocracoke nearly always maintains a fresh water lens that is about 10 - 15 feet thick, and which lies about 4 - 5 feet below the surface.
[Ground water can be] clear and sweet-smellingthough [it] is sometimes darker with an odor. In any case it is always perfect for watering plants or rinsing off after a day at the beach. And a well point and pump can be installed here in less than a day!

Out latest Ocracoke Newsletter is a reprint of a 1948 article about the Mail Boat Aleta, "Boat Hauls Mail, More." You can read it here:


  1. Anonymous9:34 AM

    Is the water , the tap water, er what does it taste like? Is it recommended that visitors bring their own bottled water?. I have recently returned from staying on an island and the water was salty. It took some getting used to and my coffee did taste , well, It was a different coffee maker ... I did not have my gold filter ..and well What does the OI water taste like????

    1. Ocracoke municipal water is drawn from the Castle Hayne aquifer, hundreds of feet below the surface. It is processed by a sophisticated reverse osmosis filtering system, and is extremely pure & virtually tasteless.

      When the system was installed, 40 years ago, the filters were not as effective, and the water was slightly saline. That is no longer the case.I would leave the bottled water home.

  2. Anonymous7:29 AM

    Ahh, I recall this story, but it was good to read it again. Thanks for the re-post, Philip. How fares the pump and well these days? Still going strong? And as for your initial digging endeavor, did you determine the length of the well pipe based on lore and the past success of others, or was there a bit of dead reckoning involved as well? A fine story by Lou Ann, and a noteworthy accomplishment by you that's hopefully still bearing fruit today.

    Thanks again, and as always, for sharing your island adventures.

    1. I put new leathers in the pump last season, and it is still working well. I believe it may be the last working pitcher pump on the island. The general rule is to use "a point [a well point] and a joint [a 5' section of pipe]." That usually puts the point right into the fresh water lens. If you put your pump on a hill it will take a bit more pipe.

  3. Julie S.1:48 PM

    Wonderful story! My husband wants to know if you will give "pump drilling lessons" when we retire to the island! Are there really no other island folks with a well like this? Seems ideal for watering a garden, rinsing a salty human or dog, etc.

    1. Other folks have well points in the ground -- connected to electric pumps -- but I can't think of anyone else who has a working hand pump.