Risk factors associated with perceptions of drinking water quality in rural Saskatchewan

Figures & data

Figure 1. Causal diagram used to guide model development for each of the outcomes.

Table 1. Total numbers of complete and missing responses and the proportion of respondents at each level for each of the outcomes modeled and risk factors evaluated.

		Complete	Missing	Response	Frequency
		n	n		n	%^a
Outcomes
	Any aesthetic complaint about tap water	1984	81	Yes	501	25.3
				No	1483	74.8
	Believed tap water not safe to drink	1984	81	Yes	235	11.8
				No	1749	88.2
	Fear tap water will become contaminated	1988	77	Yes	706	35.5
				No	1282	64.5
	Someone had been ill from tap water	1784	281	Yes	57	3.2
				No	1727	96.8
Risk factors
	Private water supply	2059	6	Yes	1249	60.7
				No	810	39.3
	Community (treated) water supply	2059	6	Yes	640	31.1
				No	1419	68.9
	Water delivered by truck	2056	9	Yes	119	5.8
				No	1937	94.2
	Used a public water station	2059	6	Yes	121	5.9
				No	1938	94.1
	Had a cistern	2027	38	Yes	292	14.4
				No	1735	85.6
	Ground water source	1857	208	Yes	1349	72.6
				No	508	27.4
	Surface water source	1856	209	Yes	613	33.0
				No	1243	67.0
	Ever had a water advisory	1981	84	Yes	485	24.5
				No	1496	75.5
	Home is in a town	2047	18	Yes	525	25.6
				No	1522	74.4
	Gender	2005	60	Female	1053^b	52.5
				Male	952	47.5
	Age	2050	15	< 45 years	317^b	15.5
				45–54 years	446	21.8
				55–64 years	614	30.0
				≥ 65 years	673	32.8
	Number of years in community	2046	19	≤10 years	403^b	19.7
				> 10 years	1643	80.3
	Children reside in home	1932	133	Yes	437	22.6
				No	1495	77.4

^a Percentage based on number of complete observations.

^b Reference category.

Table 2. Comparison of key demographic variables between the sample population and the Statistics Canada 2011 Census of Population for the rural census subdivisions included within the survey regions.

Category	Survey respondents^a		2011 Census of Population (%)
	N	(%)
Female	1053	52.5	47.3
Male	952	47.5	52.7
18–45 years	317	15.5	35.7
45–54 years	446	21.8	23.2
55–65 years	614	30.0	21.7
≥ 65 years	673	32.8	19.3

^a Total number of respondents: 2005 for gender and 2050 for age.

Table 3. Proportion of respondents identifying each type of aesthetic complaint overall and by the type of water source used.

Complaint	All respondents (n = 1984)	By type of water source used
		Ground water (n = 1293)	Surface water (n = 592)	Private supply (n = 1194)	Community supply (n = 620)	Delivered by truck (n = 114)	Public water station (n = 119)
Odor	12.5%	10.5%	13.0%	12.3%	13.7%	7.9%	14.3%
Taste	14.5%	13.1%	13.7%	11.5%	20.3%	5.3%	19.3%
Discolored	11.2%	11.1%	10.1%	13.4%	7.7%	2.6%	13.4%
Cloudy	4.8%	3.5%	6.6%	4.8%	4.0%	2.6%	5.9%

Table 4. Risk factors significantly associated with having any type of aesthetic complaint with the household’s tap water in the final multivariable model.

Risk Factor	OR	95% CI	p value
Trucked water delivery	0.5	0.3, 0.9	0.02
Ever had a water advisory	1.8	1.4, 2.3	< 0.001
Male	0.7	0.6, 0.9	0.005
Female	REF		< 0.001^a
Age
Age < 45	REF
Age 45-54	0.6	0.4, 0.9	0.006
Age 55-64	0.6	0.4, 0.8	< 0.001
Age 65+	0.4	0.3, 0.6	< 0.001
≤ 10 years in community	REF
>10 Years in community	0.7	0.5, 0.9	0.007
Random Effects	Variance	SE
Postal Code	0.140	0.073
Region	0.034	0.040
Number of observations = 1865

Note:

OR: odds ratio. CI: confidence interval. REF: reference category. SE: standard error.

^a Wald Type III test of fixed effect for age

Figure 2. Predicted probabilities of having any aesthetic complaint, comparing those who had a drinking water advisory to those who did not, for men and women in each age category averaged over the use of water delivered by truck and length of time residing in community. CI: confidence interval.

Table 5. Risk factors significantly associated, in the final multivariable model, with the perception that household tap water is not safe to drink.

Risk Factors		OR	95% CI			p value
Community treated water supply		0.2	0.1, 0.3			< 0.001
Any aesthetic complaint		4.6	3.3, 6.3			< 0.001
Ground water source x ever had advisory						0.02^a
	Use a ground water source compared to not using ground water for those who have ever had a water advisory	1.1	0.6, 2.0			0.77
	Use a ground water source compared to not using ground water for those who have not had a water advisory	0.4	0.3, 0.7			0.001
	Ever had an advisory compared to not having had an advisory for those who use a ground water source	7.3	4.6, 11.5			< 0.001
	Ever had an advisory compared to not having had an advisory for those who do not use a ground water source	3.0	1.6, 5.6			0.001
Variances of Random Effects		Variance	SE
Postal Code		0.039	0.080
Region		0.003	0.030
Number of observations = 1734

Note:

OR: odds ratio. CI: confidence interval. SE: standard error.

^a Type III test of fixed effect for interaction

Figure 3. Predicted probabilities of believing the tap water is not safe to drink for the interaction between reporting a drinking water advisory and use of a ground water source, separated by whether or not an aesthetic complaint about the water was identified, and averaged over the use of a community water supply. CI: confidence interval.

Table 6. Summary of the analyses for all water-quality or risk-perception outcomes, including the number of observations used and the risk factors associated with the final model for each outcome (effect modifications italicized).

Model	n	Increased odds of having outcome	Decreased odds of having outcome
Any aesthetic complaint	1865	Ever had advisory	Trucked water delivery
			Male
			Increasing age
			Lived in community > 10 years
Tap water not safe to drink	1734	Aesthetic complaint	Community water supply
		Had a water advisory –magnitude of effect greater for ground water users	Use a ground water source, but only for those who never had water advisory
Fear water will become contaminated^a	1784	Ever had a water advisory	Community water supply
		Age 45–64 more likely than ≥ 65	Lived in community > 10 years
Anyone ever ill from tap water	1671	Aesthetic complaint	Private water supply
		Ever had an advisory	Community water supply

^a Adjusted for whether or not children reside in home.

Statistics Canada. 2011. Census of Canada, 2011: Profile of Census Subdivisions (public-use microdata file). Ottawa ON: Statistics Canada. Using CHASS (distributor). http://datacentre2.chass.utoronto.ca.cyber.usask.ca/cgi-bin/census/2011/ (accessed December, 2013).

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