Thursday, June 23, 2016

He Always Has Brown Water after a Storm

I often get questions from readers and as part of the VAMWON network. Often the questions do not have enough detail for me to be helpful. Like when someone tells me their well stopped working what’s wrong. My first thought at those times is to secretly think “I don’t know, my crystal ball isn’t working.” Usually, I just begin asking questions. To be of any help I need information on your well, a description of the problem and its history and pictures would be helpful. Recently I received the following in response to my blog on storm impacted wells:

“I am not sure if you could share some thoughts as I have had a problem with my 38 foot deep 2 foot Diameter shallow well in rural Spotsylvania County that I have been fighting for the past 9 years. My issue is pretty synonymous with the symptoms which you stated.
The water pumped into the house from the well by way of the internal well pump will stay brown for about 2 weeks after a series of heavy rainstorms. Consequently, we always use bottled water during that time and wait for things to clear up.
I have regularly tested the well after things have cleared up over the years by using the WaterSafe test kit and have never noticed bacteria. (I have never tried it when it was brown though).
The water entering the house is pre-filtered by a pleated 10 inch 50 micron filter. When the heavy rains start, I have (with some success) put in a 5 micron carbon filter in it’s place. This seems to help when things aren’t so bad, but it doesn’t do very much when there are storms going on for days on end  like the ones we had.
I was thinking of going with an even lower micron filter as a temporary measure when the storms are bad. I know it probably won’t last more than a week, but if I knew the right micron, it might work. (I am very surprised that I am getting colored sediment even with a 5 micron filter though.”

I responded to the email: 
Wow, 38 feet is a very shallow well and likely to be impacted by surface infiltration, and drought. Typically rain water and snow melt percolate into the ground and the deeper the well the further away is the water origination and the older the water. The groundwater age is a function of the depth of the well, the geology of the area, the precipitation, recharge of the aquifer and pumping rates of the aquifer that control the rate of flow of water to a well. The age of the water in an aquifer provides insight into the likelihood of contamination from both anthropogenic and natural sources. Very young groundwater that has recently infiltrated into the aquifer is more vulnerable to contamination from human activities near the land surface than older, deeper groundwater that has had more time to be filtered by soils. Old groundwater, however, is not necessarily free of contaminants. The older groundwater can contain naturally occurring chemical elements and contamination from years past. The land surface through which groundwater is recharged must remain open and uncontaminated to maintain the quality and quantity of groundwater. 

It is always best to do a complete water analysis while the water is still brown to ensure that there is not another cause for the discoloration. Also, you do not indicate what you tested for, there are other causes of brown water, but it is a reasonable guess given your history that you are not experiencing episodic iron. However, you really should spend the money to do a complete analysis both before and after the water clears.

Filter cartridges for sediment removal are rated in microns. As you know, the micron rating for a water filter is a way of indicating the ability of the filter to remove contaminants by the size of the particles. A filter that is marked “5 microns” has some capability in capturing particles as small as 5 microns. However, there is no one accepted method to measure and describe the size of particles that a filter can capture or the total amount of particles that the filter can hold. Filter micron ratings for water are usually Nominal or Absolute. For sediment removal, Nominal rated cartridges are most common. Absolute ratings are needed for example, in removing Giardia, a type of parasite, when it becomes important that the filter cartridge absolutely must be rated at 1 microns. A Nominal Micron Rating (NMR) usually means the filter can capture a given percentage of particles of the stated size. For example, a filter might be said to have a nominal rating of 90% at 10 micron.

The breakthrough you are experiencing could possibly be resolved by having two or three filters in series, a 50 micron followed by a 25 micron followed by a 5 micron; however, I have a basic concern that there is the possibility that your well could be impacted not only by bacteria but by parasites and spores that have the potential to be fatal in vulnerable populations. Though I would encourage you to drill a well at least 100 feet below grade to ensure the health of your family, surface water can be treated. You need a series of filters meticulously maintained to reliability remove the discoloration, a series of two or three should do it. (This will impact your water pressure that you may need to boost it.) Make sure you match the flow to the capacity of the filer. Then after the water is clear you need to disinfect using a using a UV light.

Finally, you will need a point of use filtration system for any water that is likely to be drunk because of the potential for cysts, parasites etc. Giardia is a fairly common microscopic parasite that causes diarrhea. Once an animal or person is infected with Giardia, the parasite lives in the intestine and is passed in feces. Because the parasite is protected by an outer shell, it can survive outside the body and in the environment for long periods of time extending to months. Millions of Giardia parasites can be released in a bowel movement of an infected human or animal. Human or animal waste can enter water through sewage overflows from flooded septic systems, polluted storm water runoff, and agricultural runoff. Wells may be more vulnerable to such contamination after flooding, particularly if the wells are shallow, have been dug or bored, or have been submerged by floodwater for long periods of time.

The CDC usually recommend boiling water, but that may be impractical unless you are sure that the water is impacted. An alternative to boiling water is using a point-of-use filter. Not all home water filters remove Giardia. Filters that are designed to remove the parasite should have one of the following labels:
  •  Reverse osmosis,
  •  Absolute pore size of 1 micron or smaller,
  •  Tested and certified by NSF Standard 53 for cyst removal, or
  •  Tested and certified by NSF Standard 53 for cyst reduction.

I hope this helps.

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