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With the drought, some homeowners with their own wells suddenly run out of water.  How to know if you’re at risk?  The best way is to know the level of water in your well, relative to the location of the pump.  When the well’s water level reaches the pump, you’re out of water.  


The most common method of measuring the water level is by dropping something down the well - typically a probe is lowered until it detects the water level by electrical conductivity. This is usually done when the pump is off, and measures the "static" water level, which is the highest.  This provides useful information, but does not tell the whole story.  Two other measurements are helpful, particularly if the static level is getting close to the pump (for example, within 20 feet):

  1. How far does the water level drop when the pump runs?  When running, the pump usually takes water out of the well faster than in can be replenished from the surrounding aquifer, so the water level will temporarily drop and then return to the static level some time after the pump stops.  If this temporary water level drop gets to the level of the pump, your water delivery will be interrupted, and the pump could be damaged if it cannot sense low water and stop automatically.

  2. How fast does the groundwater refill the well after the pump stops?  Often, if the well is not in a good water bearing aquifer, it will take significant time for the water to seep back into the well.  Or, older wells can get clogged, or build up deposits, that slow the rate the water can get into the well even in a good aquifer.  These can cause a well to be "low yield" - meaning the well cannot sustain a good flow long enough to, say, fill a bathtub.  Low yield wells often need a large storage tank and booster pump to have enough water readily available for normal household demand.


I use a sonic level sensor – which repeatedly sends a sound pulse down the well every few seconds, which echoes back from the water surface.  The sensor times how long it takes for the echo to return, and calculates the water level depth.  This way, I measure how far the water drops when the pump runs.  A measurement of one pump cycle may be enough to know if you have plenty of water.  I can also record the level for a day, if the water level is getting close to the pump, to get the full picture on how your particular water use impacts the well.

If we find the well is likely to run out of water, there are steps you can take:

  1. If you’re using too much water at one time, as might happen with irrigation, spread the usage out to let the well recover between pump runs.

  2. You may be able to lower the pump (a job best done by a well company) to make more of the groundwater available to you.

  3. Have the well drilled deeper - if more water bearing formation is available.

  4. Add a storage tank and booster pump to meet high demand periods, or enable you to have water hauled in.

ECMC is able to offer this level measurement service throughout Sonoma County, California. 

Use the contact form below, or email, or call 707-861-6649 to learn more, request a quote, or schedule your measurement.

Use the links below to learn more about these services:

Well Level Testing

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