Nitrate (N03l level of drinking and irrigation water sources in AI-Qassim
Region-Central Saudi Arabia was Investigated. The obtained analytical results indicate
that there is a considerable variation in NOl' level between the municipal network
water supply and domestically produced bottled water on one hand and well water on
the other hand. The mean of NO; level of the latter (69.7mgL·') is above the
maximum permissible level (45 mg L") set by the local and international standards
and guidelines. Of the 40 well water samples examined only 23 (57%) comply with the
guidelines set for the maximum permissible level set by most of the standards.
Statistical analysis (Correlation) revealed a Significant reciprocal relationship between
depth of well and NOli- level (P< .01, R²=0.293).