The grade of irrigation water available to irrigators has a significant impact on crops as well as yields. Therefore, it is a need to better understand irrigation water quality. The present study mainly focuses on the assessment of the suitability of water of forty-four fixed bore wells of Kanchipuram district, Tamil Nadu, India. The groundwater sample datasets of post-monsoon (2005–2013) and pre-monsoon (2006–2013) season were collected for 9 years. Water quality indices, namely sodium adsorption ratio, exchangeable sodium percent (SSP or %Na), residual sodium carbonate (RSC or RA), Kelly’s ratio, permeability index, chloroalkaline indices (CAI1 and CAI2), potential salinity (PS), magnesium hazard, total dissolved solids and total hardness, have been calculated for separate bore wells. The r₁ and r₂ indices show that groundwater of the study area is Na⁺–SO₄²⁻ and deep meteoric percolation type. Majority of the wells are fall under moderate to unsuitable category of water for irrigation purposes. Further, wells water has also been classified on the base of meteoric genesis index.

The water quality data of fixed 44 wells were monitored during post- and pre-monsoon season 2005–2013 of Kanchipuram district of state Tamil Nadu, India. Water Quality Indices (WQIs) methodology was applied to categorize groundwater on the basis of rating. In total, 13 groundwater quality parameters: calcium (Ca²⁺), magnesium (Mg²⁺), sodium (Na⁺), potassium (K⁺), bicarbonate (HCO₃ ⁻), nitrate (NO₃ ⁻), chloride (Cl⁻), fluoride (F⁻), sulphate (SO₄ ²⁻), total hardness (TH), total dissolved solids (TDS), hydrogen ion concentration (pH) and electrical conductivity (EC) were taken for statistical analysis. Three different WQI models were computed using a decadal physicochemical water quality data mainly for drinking (WQI₁ and WQI₂) and irrigation (WQI₃) need. The WQIs variability thematic maps were generated in the Geographical Information System environment through ArcGIS software. These spatial distribution maps of WQI provide a detailed overview. The work outlined that the groundwater of the area is impaired by the anthropogenic activities and needs proper management plan to control further contamination and pollution of the groundwater of the area. Further, the groundwater of few monitoring wells needs a proper treatment before its consumptive uses. The alternative water supply should be provided to local inhabitants for daily uses.

Groundwater quality of Chennai, Tamil Nadu (India) has been assessed during different seasons of year 2012. Three physical (pH, EC, and TDS) and four chemical parameters (Ca²⁺, Cl⁻, TH, Mg²⁺ and SO₄²⁻) from 18 bore wells were assessed. The results showed that pH of majority of groundwater samples indicates a slightly basic condition (7.99_post-monsoon and 8.35_pre-monsoon). TH was slightly hard [322.11 mg/l_pre-monsoon, 299.37 mg/l_post-monsoon but lies under World Health Organization (WHO) upper limit]. EC, TDS, Ca²⁺ and Mg²⁺ concentrations were under WHO permissible limit during post-monsoon (1503.42 μS/cm, 1009.37, 66.58 and 32.42 mg/l respectively) and pre-monsoon (1371.58 μS/cm, 946.84, 71.79 and 34.79 mg/l, respectively). EC shows a good correlation with SO₄²⁻ (R² = 0.59_pre-monsoon, 0.77_post-monsoon) which indicates that SO₄²⁻ plays a major role in EC of ground water of bore wells. SO₄²⁻ has also showed positive correlations with TDS (R² = 0.84_pre-monsoon, 0.95_post-monsoon) and TH (R² = 0.70_pre-monsoon, 0.75_post-monsoon). The principal component analysis (PCA)/factor analysis (FA) was carried out; Factor₁ explains 59.154 and 69.278 % of the total variance during pre- and post-monsoon, respectively, with a strong positive loading on Ca²⁺, Mg²⁺, SO₄²⁻, TDS and a negative loading on pH. Factor₂ accounts for 13.94 and 14.22 % of the total variance during pre- and post-monsoon, respectively, and was characterized by strong positive loading of only pH and poor/negative loading of EC, Ca²⁺, Mg²⁺, SO₄²⁻, TDS and TH during pre- and post-monsoon. We recommend routine monitoring and thorough treatment before consumption. Further, this study has demonstrated the effectiveness of PCA/FA to assess the hydrogeochemical processes governing the groundwater chemistry in the area.