Monday, July 11, 2016

Conversations about Wells Going Dry

Regularly, I receive questions about people’s wells through my blog. If you send your email address I will try to be helpful, but there are limits because often there is not enough information.I received the following question: 

I just came across your blog and had a question for you.. We just bought our home and have been here almost two weeks, last night we had no water and this morning we do. Does that mean our well is running dry?  We've never had well water, so we're lost.”

I responded that it could, indeed, mean that their well is running dry; but it could also mean that you overused the well. Let's get some more details. How old is the well? What type of well is it and how deep is the well? Where are you? Do you have the well completion report? Did you test the well recharge rate when you bought the house? How much water did you use yesterday (showers, laundry, watering the lawn)? Please send me all the details you have and let's see if we can figure this out. 
Honestly, I don't know the answers to those questions. I do know a lot of water was used yesterday, between everyone taking showers and my son out watering. I also did a lot of laundry. My son went and checked the holding tank, and I guess it had 300 gallons in there this morning. We live in San Tan Valley, AZ.”

That is very little information, it is important when you buy a house with a well, that you gather more information on the well and local ground water conditions. They live in southeast Arizona and the well has limited enough flow that the system has a holding tank. These type of holding tanks (sometimes called cisterns) are used with low flow wells that need to store all the water the well can produce in a 24 hour period. Also, a quick look at theDrought Monitor told me that region of Arizona is in drought conditions. Checking with the state department of water they say “Winter precipitation this year was well below average for an El Niño winter. The winter season had a strong start in November through January, then the storms stopped coming into Arizona. Most of the storms that crossed Utah brushed by northern Arizona, but left central and southern Arizona quite dry.”

               In general watering is inadvisable in a desert when you have a well especially when in long periods of drought. Groundwater is found in aquifers below the surface of the Earth. This water supplies all wells- private, public and irrigation. The amount of groundwater that can be sustainably used is determined by the amount of rain and snow melt that recharges the groundwater each year and the storage capacity of the geology for variation between wet and dry years. Nature determines the amount of water that is available- geology, weather and climate. The cistern filling to 300 gallons overnight is an indication of how much water you will have available to use. During dry periods, there is little rainfall to refill the groundwater, but water use continues. Not too surprisingly, during a drought, and the dryer parts of the year the groundwater level will fall. Clearly, with 300 gallons recharging the cistern the well is not dry, but it is a low producing well. You might want to contact the Arizona Department of Water Resources and find out what records might exist for your well. Current Arizona regulations require the well driller complete a well driller’s report, including a well log. The information required includes:
  • depth of the well
  • depth to the water
  • type and size of casing, and
  •  kind of material used in well construction 
  • the well yield test determines the quantity of water your well can produce

Based on generating 300 gallons overnight the current yield on your well is less than a gallon a minute. If this rate remains steady and not falling any further it is enough to run a household using conservation, but clearly inadequate to water your yard.

               Over time the amount of water a well produces can decrease. Sometimes that is because the water table is dropping. Other times it can be caused by the plugging of holes in the well casing, mineral encrustation of the well screen or the filling of openings in the geologic formation around the well from which water flows as discussed above. The pump performance could also be impaired by a damaged motor or impeller. Depending on what the problem is sometimes this can be fixed. The solution cannot be properly identified until the cause of the problem is identified. A well check-up should be performed regularly and whenever a problem is noticed. This check-up should include four components. First, is a flow test to determine system output, along with a check of the water level before and during pumping (if possible). Second is to check pump motor performance (check amp load, grounding, and line voltage), pressure tank and pressure switch contact, and general water appearance. (This will not necessarily identify a pump that is going to fail shortly). Next, is an inspection of well equipment to assure that it is sanitary and meets local code requirements. Third, a test of your water for coliform bacteria and nitrates, and anything else of local concern should be performed. These tests while not exhaustive, should allow you to differentiate between a pump problem, well/water supply problem, and other system problems.

               In the meantime you need to live within your water budget. You only have the water available to you that your well is generating. There are tremendous differences in water consumption of appliances and fixtures based on their age and design. For example low-flush toilets which use 1.6 gallons per flush versus 5 gallons per flush for the older toilets. According to the 2001 Handbook of Water Use and Conservation by A. Vickers and published by WaterPlow Press in Amherst, MA the average person flushes the toilet 5.1 times a day. Before the advent of low flush toilet, flushing was the largest use of water for each person. If you have new toilets your daily water use for flushing would be 8.2 gallons versus 25.5 gallons for an older toilet. Compressor assisted toilets (commonly used in highway rest stops) only use 0.5 gallons of water and if widely adopted could reduce flushing use of water to 2.6 gallons per day per person. Other toilets that have separate flush cycles for fluid can also save water, and of course there is the California strategy of not flushing after only urinating to minimize the daily number of flushes. Changing your toilets and flushing behavior turns out to be the single most effective water conservation strategy a household can implement. Thank goodness, there are now powerful flushing low flow toilets.

               The typical American uses the most water (indoors) for flushing, showering, washing hands and brushing teeth, and laundry. Buying water efficient appliances and fixtures and changing behavior can significantly reduce our water use. For bathing and brushing teeth low flow faucets and showerheads and behavior modification (not running the water while you brush your teeth, shorter showers or not running the water while you lather up can save about a third of the water typically used for personal hygiene, reducing the typical 28 gallons a day to 19 gallons a day. Laundry is the second largest use of water after toilets. Try not to do more than one load of laundry a day.  A top loading washing machine uses 43-51 gallons per load while a full size front load machine uses 27 gallons per load and some machines have low volume cycles for small loads that use less. Replacing a top load washing machine with a front load machine saves 6-9 gallons of water per person per day or 24 gallons per load of laundry. A standard dishwasher uses 7-14 gallons per load while a water efficient dishwasher uses 4.5 gallons per load.

The most water used in dessert environments is for outdoor watering. A hose typically runs at 3 gallons or so a minute. Eliminating the watering of your ornamental garden would significantly reduce water use especially in Arizona. You need to have desert landscaping or to only water plants very selectively. Be mindful of your water use and it possible to live with a well producing about a half a gallon a minute with a large household for years without any problems, 
Best,

Elizabeth Ward

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