Description | Specific Indicators | Corresponding Mandatory Objectives | Corresponding National Indicators | Data Sources | Survey Questions | Alternative Data Sources | Analysis Check List | Method of Calculation | Basic Categories | Indicator Comments | Definitions | Cross-References to Other Sections | References


Description

• Percentage of households that get their tap water from a private well by type of well.
• Percentage of wells that have been tested at least three times in the past 12 months.

• Percentage of households on private wells
• Percentage of households with a shallow/bored well
• Percentage of households with a deep drilled well
• Percentage of households with a private well that has been tested for bacteria at least three times in the past 12 months

 
Corresponding Mandatory Objectives

Program Standard: Infectious Diseases, Safe Water

• To ensure that community drinking water systems meet the health-related chemical, physical, microbiological and radionuclide objectives as published in the Ontario Drinking Water Objectives (revised 1994) and the Guidelines for Canadian Drinking Water Quality (sixth edition).

• None

Question safe_w1 “Do you get your tap water from the municipal system or a private well?” 1) municipal system, 3) private well, 4) natural non-well water that is NOT part of the municipal system, for example, the R may get their water from a nearby spring, pond, lake, etc., 5) some other water system/describe the system (specify), 8) don’t know, 9) refused

Question safe_w2 “Is the well deep-drilled, shallow dug or bored well, or another type of well?” 1) deep-drilled (if required: wells that are more than 21 feet deep), 3) shallow dug or bored (includes tile, ring, dry, Indian, sprint water, hand dug, point, spring, sand point, steet, etc.), 5) some other type of well (specify) 8) don’t know, 9) refused

Question safe_w3 “How many times have you had your water tested for bacteria in the past 12 months?” 0) not tested in the last 12 months, 1-52) enter number of times, 53) more than 52 times, 98) don’t know, 99) refused

• The Ontario Ministry of the Environment and/or local Planning departments may be able to provide the number of private wells in a particular area.

• The number of “don’t know” (coded as 8 or 98) and “refusal” (coded as 9 or 99) respondents are likely small and can be excluded. Users should check numbers before excluding these non-respondents.
• For indicator on testing well water at least three times in past year, safe_w3 >= 3.
• Before releasing and/or publishing RRFSS data, users should ensure that the numerator is at least 5 and the denominator is at least 30, regardless of the estimate’s coefficient of variation. For estimates based on sample sizes of 30 or more, determine the coefficient of variation of the rounded weighted estimate and follow the guidelines below:
  • CV between 0 and 16.5: estimate can be released without warnings.
  • CV between 16.6 and 33.3: estimate can be released with warnings “High variability, interpret with caution”.
  • CV greater than 33.3: estimate should not be released, regardless of the cell size.
• No weight is applied since the data is analyzed by the number of households. The household weight need only be applied if the indicator is expressed as a percent of the total number of residents.
• A provincial sample is not available with the RRFSS.
• Refer to the RRFSS Data Dictionary at www.rrfss.ca for more information about module questions and indicators.

 
Method of Calculation

Percentage of well households with shallow/bored wells
total number of households with a shallow/bored well                          * 100
total number of households that get their tap water from a private well

Percentage of well households with deep drilled wells
total number of households with a deep drilled well                               * 100
total number of households that get their tap water from a private well

Percentage of well households tested for bacteria at least three times in past 12 months
total number of well households that tested their well water at least three times for bacteria in the past 12 months   * 100
total number of households that get their tap water from a private well

Basic Categories

• Geographic areas: RRFSS - participating health units that chose the safe water module (varies by wave, check documentation).
• Type of well: shallow/bored well, deep drilled well or other type of well.
• Number of times well has been tested for bacteria in past 12 months.

Indicator Comments

• Households receiving their tap water from a private well may be more at risk for water-borne illness than those on municipal systems, particularly if the well water is not tested regularly for bacteria.
• Well owners are legally responsible for wells on their property, and should be familiar with the laws that affect them. ’Ontarios Wells Regulation (Reg. 903) sets rules for who can construct or work on a well and construction standards for all new wells.¹
• Although boards of health are not responsible for private water supplies, they do provide free testing of water for bacteria and educate those on wells about the importance of testing.
• Wells are generally divided into shallow (dug, bored, or driven and jetted wells) and deep (drilled) wells. In general, dug wells are most susceptible to contamination because they are shallow and may lack a continuous casing. Drilled wells tend to draw water from deep, confined aquifers.
• Owners should have a copy of their well record which is also retained by the Ministry of the Environment. The well record contains information such as the date constructed, location, contractor identification, casing material, as well as various technical information about the well.
• Bacterial contamination of shallow wells generally comes from surface contamination such as run-off from lawns or agricultural manure spreading activities.
• The Public Health Laboratory of the Ministry of Health and Long-Term Care (MOHLTC) routinely tests water samples for Total Coliforms and E.coli and can also test for the presence of nitrate and/or nitrite and/or fluoride. Private companies can do more extensive chemical testing for a charge.
• Guidelines with regards to the frequency of well testing are inconsistent across health units. The MOHLTC suggests testing three times a year on their web site.²
• Chemical levels in well water might be monitored twice per year for the first year that a well is in operation, and then once per year for all other years. Additional sampling may be necessary following heavy rainfall, flooding, or manure or chemical contamination. Owners may want more extensive testing if household members include pregnant women or young children.
• Not all health units participate in RRFSS, and not all health units participating in RRFSS ask the safe water module. No provincial estimates are available.

• Deep-drilled well - Deep-drilled wells are deep wells (15m (50ft) to 60m (200ft or more)) that are excavated using rotary hydraulic or percussion drilling equipment. The casing of a drilled well is usually steel. The well head may extend above the ground or be contained in an access pit.
• Shallow well - Shallow (dug) wells are typically shallow (9 meters/30 feet or less) and excavated by hand or backhoe. The well walls are often lined with rocks, bricks, wood or concrete.
• Bored well - Bored wells are shallow (15 meters/50 feet or less)) and dug with a boring rig or a power driven earth auger. The bored well is typically lined with concrete tile or corrugated pipe.

• None

 
References

1. Ministry of the Environment. Wells. URL: http://www.ene.gov.on.ca/envision/water/wells.htm
2. Ministry of Health and Long-Term Care. Water Safety: Putting Your Well Water to the Test. URL: http://www.health.gov.on.ca/english/public/pub/watersafe/watersafe_welltest.html
3. Ministry of the Environment. Green Facts: The protection of water quality in drilled wells. September 2003. http://www.ene.gov.on.ca/cons/3961e01.pdf
4. Ministry of the Environment. Green Facts: The protection of water quality in bored and dug wells. September 2003. http://www.ene.gov.on.ca/cons/3962e01.pdf

 
Date of Last Revision: May 24, 2006 .