One lawyer’s overly simplistic South Sound hydrological model

Note:  This is “sub” post that supports other blog entries.

Before embarking on my overly simplistic explanation of Western Washington ground water hydrology, I should disclose, I have a chemical engineering degree and worked as a petroleum reservoir engineer for five years before law school.  I have a reasonably good understanding of the physics governing water flow through an aquifer, wells, treatment systems, and piping, but I definitely am not an expert in the local hydrology or aquifers.  You should consult such an expert about your particular circumstances.

With that disclaimer, the first principle is that actual amount of precipitation we receive over the course of a year hardly ever equals the 50″ average annual precipitation recorded between 1897 and 2015 (using Olympia airport NOAA data).   In 1999, for example, we got a whopping 65″ of precipitation.  The very next year we received only 36 inches.    The average annual precipitation for those two years was 52″ (close to our long term annual average), but one year was unusually wet and the next unusually dry.   The hydrological conditions in your aquifer were likely dramatically different in those two summers and different from conditions that exist in the “average” year.

Second, South Sound watersheds receive a lot more precipitation (about 85% of the annual total) from October 1 through April than during the rest of the year.    On average the Olympia airport receives about one-half inch rain for all of July.  In November, December, and January, there are many single days that receive that much precipitation

Third, the groundwater reservoir (aquifer) that your water well taps into is probably hydraulically connected to the aquifer that  your neighbors are (or will be) pumping from and to the surface water bodies (i.e., streams and lakes) that recharge the aquifer.   Those hydraulic connections mean that your groundwater withdrawal will to some extent reduce the amount of water available for your neighbors to pump and/or the water available for aquifer recharge. Correspondingly, your neighbor’s groundwater withdrawals will reduce the amount of water available for you to pump from the aquifer.     Equally important the amount of precipitation received in the watershed affects the aquifer recharge and the amount of groundwater available for your well.

These principles result in the observation that local groundwater levels typically peak around March 15th and reaches their lowest level in November although those dates can vary significantly in any year.   The seasonal variation in ground water levels is easily seen in measurements taken in wells.   For example in published data from water wells located in the Scatter Creek area of South Thurston and North Lewis County, the recorded static water levels typically varied by 15 feet between the wet and dry months of the same water year.  That variation caused some water wells (i.e., those  with pumps set above the lower  static water level) dry up in the summer and fall. This hydraulic variability is not a recent phenomenon; although  population growth (i.e., more wells sucking from the same aquifer) exacerbates the effect. Since the 1950’s summertime groundwater shortages have been reported by homeowners in the Scatter Creek area.

South Sound water well buyer beware

For newcomers to the South Sound, it may seem hard to believe that anyone living here could ever find themselves short of healthful drinking water.   With an annual average of 50 inches of precipitation per year, the South Sound riddled with beautiful mountain fed streams and lakes.    Despite this natural bounty, many of our rural neighbors do indeed run out of  well water during the summer.  To make do some borrow a neighbor’s shower or have water hauled to the home.

In this post, for prospective rural homebuyers, I identify some risks associated with buying a residential property with an existing water well in rural Thurston County property.  I  suggest steps that prospective rural home buyers concerned about their future domestic water supply can take to avoid disappointment.   The water well-related risks of purchasing raw land and the impact of recent Washington State Supreme Court decisions on undeveloped rural land in the South Sound will be the subject of future posts.

South Sound Drinking Water Wells

“Domestic” water includes that used for normal in-home uses such as drinking, cooking, bathing, washing dishes and clothes, and so on.  Domestic use may include residential outdoor uses such as lawn and garden irrigation, and washing cars.  Rural property owners in the South Sound generally get their domestic water from a privately owned groundwater well.

In fact, if you live outside of a designated urban growth area, you probably could not legally connect to a municipal water supply even if one was available nearby.   Instead (unless your home is connected one of a few private water systems)  you will be a so-called self-supplied domestic water user whose domestic water is supplied by a private one or two-party well.

Generally speaking most residential property buyers are concerned about the quality and quantity of the domestic water available in their home.  Quality is particularly important if you want to drink or bathe with your water.  Quantity is important because most people don’t want to run short of domestic water.

People used to getting their household water from a heavily regulated municipal water supply may be surprised to learn that in Thurston County there still is very little government oversight or regulation of water quantity or quality from single or two-family wells.  With respect to quantity regulation, no water right permit is required for single or group wells supplying up to 5000 gallons per day and presently there is no metering requirement for private wells.  After your well is drilled, effectively you can use all the water that your well is capable of supplying.  Of course, your neighbors can do the same thing if so inclined and at some point production from their well may reduce the amount of water available to your well.

Regarding water quality, wells on relatively small parcels of land are always susceptible to contamination from nearby human or animal activity.  The well water may include fecal coliform or other infectious agents or toxins.  It may also contain very high salt or mineral levels that limit its uses.

Municipal water supplies are regularly tested for many contaminants and test results are publicly available.  For example, the City of Olympia regularly tests its supplies for 28 contaminants as required by state and federal regulations.  By contrast, for private wells Thurston County requires a only a one time test for two contaminants – fecal coliform and nitrates – before it issues a building permit.  After issuing the building permit the Thurston County does not require any water quality testing for water wells serving one or two families.   The County recommends but does not require annual testing of wells for fecal coliform  and nitrates every three years.  For more on rural water quality testing click here.

Sufficient water quantity is important to ensure you can meet demand but if there is no metered flow on the well, how does a prospective buyer begin to estimate the well’s flow capacity?

First, one can look back to the information originally submitted to the County by the developer for some fundamental information.    If the developer’s proposed water source was a well serving one or two families (systems serving more than two families have additional requirements), the permit applicant was required to submit a well log report prepared by the licensed driller that describes various details about well construction and the geology encountered during drilling.   The report also contained the results of a yield and reservoir recovery tests reflecting the capacity of the well to produce water.

The original well log report was probably used by county staff to determine whether the well met minimum construction standards and was capable of delivering the required volume of water.  Although Thurston County requires that home sellers prove that their septic system is functioning at the time of transfer (the so-called TOT report), there is no similar requirement applicable to drinking water wells.  For more on current Thurston County water well requirements and for tips on getting information on wells that predate those regulations, click here.

Currently, for a single family well, the Thurston County building permit regulations require a yield of 400 gallons per day (gpd).  A yield of 800 gallons per day (gpd) is required for a two family well.  At first blush, these may seem like reasonable levels as an average family of four reportedly uses around 200 gpd on an annual basis.   In this area, however, most households use significantly more water during the summer for landscape watering, filling kiddie pools, etc.  A South Sound family that consumes an annual average of 200 gpd of water, probably uses 400 gpd or more in July or August.

The yield indicated on the well report (and used to determine compliance with County building regulations) is based on a test for permit-exempt wells (i.e., for residential developments using less than 5,000 gpd) by state Department of Ecology regulation:

Testing of a well . . .  shall be conducted at a constant rate for a period of at least one hour or longer if required by the department of health. Test pumping under this section can be either by bailer, air lift, or with a pump. WAC 173-160-321.

One can imagine that an unscrupulous developer – if there is such a person – could improve his or her odds of getting an acceptable yield for the Certificate Water Availability for a building permit by drilling and testing the well at the optimal time of year and under optimal hydrological conditions.  Alternatively, if neighbors have drilled wells into the same aquifer since the well yield test result was obtained, your well’s current production rate is unlikely to match its original yield test figure.  So, the wary prospective buyer should take yield figures from a well report with a very large grain of salt.  The “yield” that was measured during the reported test in March of 2005, for example, is probably not the yield you will actually experience next August as your neighbor waters his lawn.

To better illustrate the potentially misleading nature of a well test yield estimate for the interested prospective buyer, a brief detour into South Sound hydrology might help.  As you read through (or skip) the overly simplistic discussion of hydrologic principles, your take away should be that the yield (gallons per day or gpd) reported on the well log report was determined a single well test that was conducted under hydrological conditions that are not representative of the conditions your well will experience in the future.    In other words, the well’s past performance during that reported yield test (which could have occurred decades ago) is not indicative of the performance you will obtain from the well after you move into the home.  For more on well yield testing click here.

Well-related due diligence for buyers

With that background, how does someone looking for the rural Thurston County lifestyle avoid buying a household water problem?  By problem, I mean a household water system that does not meet the buyer’s expectations for a reliable supply of potable water.

An ad may have attracted your attention to the property.  I have examined hundreds of ads for rural property in the South Sound. I do not recall a single one that included a warning that the property had an unreliable supply of household water.  I cannot even recall a single ad teasing that the domestic water system “needed a little TLC” or was “perfect for the handy person.”  If the ad included any statement about domestic water, it typically reported the yield figure from the original well report.  As previously demonstrated, that yield figure indicates only the well’s past performance over a very short period on one day.  It almost assuredly does not represent the yield you are likely to obtain in the future.

I have also never seen an ad suggesting that prospective buyers should test the domestic water supply to their satisfaction.  So, the advertising or MLS data you see initially is unlikely to raise any red flags.

As a first step, a concerned buyer should include a well addendum (NWMLS Form 22R) in every offer for rural property served by a water well.  That form requires to make additional disclosures about the water system beyond those required by Form 17 (RCW 64.06.021) and it allows the buyer to conduct additional testing of the water quality and yield. Consult with an expert from a local drilling or engineering firm to determine a reasonable suite of water quality and yield tests and condition your offer upon the satisfactory completion of the designated tests.

After you have scheduled recommended testing,  a concerned prospective buyer should also check the Department of Ecology’s well report data base (click here) to learn about any wells drilled on the property and nearby.  Similarly, the building permit file maintained by the county may offer some insight.  Even if this research doesn’t directly provide useful information, it can help you identify neighbors with wells similar to one you are considering and then you can ask about their experience.   If the neighbor has lived on their property for several years, they can be a wealth of information.  Ask if they have ever run out of household water and if they have any trouble with their well.  Ask if they know anything about the well on the property you are looking to buy or about nearby.  Given the variability of hydrological conditions, a neighbor with historical perspective and experience can be the best source of information.

Of course human tolerance varies widely and what is acceptable to one person (i.e., trucking in drinking water and showering at an aunt’s house) may not be acceptable to you.  My grandparents spent virtually all of their adult life in a house with undrinkable well water.  The picture above this post is the pump from their well.  They drove about a mile to the “town well” to get water for drinking and making coffee and never thought twice about it.  I have met few people as hardy as them, however, and most contemporary rural residents undoubtedly have higher expectations for their household water supply.

It is logical to turn to the seller and listing broker for information but the listing broker will likely profess no independent knowledge about the well.  In Washington state the listing broker is required to disclose known to him or her that are not readily apparent to the buyer and to  “deal honestly and in good faith” with prospective buyer.  RCW 18.86.030(1)(a).   The listing broker is not required to independently investigate the condition of the water supply for the parcel he or she lists.  RCW 18.86.030(1)(d).

Now that you know those legal rules, do you think most listing agents will ask their sellers hard questions about problems with the water supply?  The listing broker can and often will accept the seller’s representation (or misrepresentations) and then pass those along to you.  Even if the listing agent learns about a material defect regarding the water system, he or she may conclude that the defect is readily ascertainable to you and therefore need not be disclosed.  So, buyers, do not count on the listing agent to disclose the true condition of the property’s water supply. The listing agent represents the seller and is primarily motivated to close the sale and get his or her commission.

If there are questions about the well, however, you should put those questions in writing to the seller and their agent.  Although they may not answer and is not prudent to trust their answers without verification, their answer or non-answer can reveal a great deal.