Once you have collected your tap water sample from your place of residence, you will need to determine the map coordinates (latitude and longitude).


Latitude and Longitude data for a specific address can be found in several ways.


  1. Use ‘Google Earth’.  To use this program, you will have to download it onto your computer.  The website for the free version is here.
    1. Once you have downloaded the program on your computer, open the program.  To find the Lat and Lon for your address, type your address (in one line) into the search box located at the upper left of your screen, then click on the search button to the right of the search box (make sure that the ‘Fly To’ tab is selected above the search box).  You should see the map zoom in on your residence.  Place the mouse cursor over your residence and write down the map coordinates that are at the bottom of the map, just to the right of the word ‘pointer’.  Be sure to record both the latitude (N) and the longitude (W).  If you have trouble with this, I can help you out.
  2. Use a GPS device if you have one.
  3. Use a detailed map.



Students were asked to bring in a tap water sample from their homes to analyze for Mg and Ca, two of the main components leading to "hard" water.  The purpose of this study was to give students experience in analyzing real samples and to determine what areas around Sacramento have "soft" or "hard" water.

Summary of Results:
Students have brought in tap water samples from their homes, have analyzed the samples, and have reported the results.  To improve the data quality, a number of quality control (QC) criteria were used to discard suspect data.  Only a fraction of the data generally meet the QC criteria.  Note that not all of the data quality issues have been addressed.  There may have been sampling errors (e.g. collection of water from a tap with a water softener) or mistakes in dilution or calculations.

The following links are to data that has been collected during some previous semesters:

Regional map of Ca2+ dataLocal map of Ca2+ data

Regional map of Mg2+ dataLocal map of Mg2+ data

Table of average data for both Ca2+ and Mg2+

Most of the water in the Sacramento region either comes from local ground water sources or from local river sources (mainly the American River for most of the samples).  The data table showed that water samples from the Sacramento Region to be softer on average than from surrounding areas (such as Davis and Yuba City). However, the map values do show water from foothill towns (Folsom and Cameron Park) to have soft water.  Within the Sacramento region, water was found to be soft near campus on the south side of the American River, while being the hardest close to CSUS but on the north side of the American River.  I am guessing that most of the samples with higher Mg and Ca concentrations originate from ground water, while many of the softer water samples from Sacramento originate from the American River.  One can expect that the ground water concentrations will tend to increase going from the east to the west, since the general flow of water will be from east to west (at least on the east side of the Sacramento River).