**5. Sources of water in Nigeria**

Globally, the provision and supply of adequate water to the populace is one of the core responsibilities and duties of the government. This is because water is among the first requirements in the hierarchy of citizens' needs and a failure to guarantee water supplies to those that need it most can lead to serious political setbacks [38]. A good knowledge of the source(s) of water is necessary to improve on the provision and supply of water to the populace. Nigeria is divided into six geological zones, namely, North-east, North-west, North-central, South–south, South-east, and South-west (**Figure 1**). The country has six hydrological basins covering the swampy forest in the south, the dense rainforest in the east, hilly shrub lands in the middle belt, savannah grasslands in the north, and semi-arid areas in the far north [38]. There are two major river systems in the country: the River Niger and River Benue both meet at Lokoja. River Niger enters the country from the northwest and River Benue enters from the northeast [39].

The most available sources of water for most urban–rural communities in developing countries, including Nigeria, are surface waters (rivers, streams, ponds and lakes) and groundwater (in form of boreholes and hand-dug wells). Surface waters in Nigeria are usually contaminated with domestic, agricultural, and industrial wastes and cause many water-related diseases and ill health to living organisms [40, 41] while Nigerian groundwater quality is generally good but these waters are often laden with high contents of heavy metals (e.g., Fe, Mn, Cd, As Hg), nitrates, fluorides or cyanides and can be contaminated with a wide variety of pathogenic organisms (often above recommended WHO levels).

A larger part of the Nigerian populace are self -dependent in meeting their daily water provision from natural sources: rivers, streams, ponds, rain and hand-dug wells or modern supply sources which include public sector supplies or private and commercial borehole businesses [42]. Access to adequate water supply in Nigeria is hampered by geographical, socio-economic and institutional factors. Reports from the WHO/UNICEF [43–45] indicate that 72% of urban dwellers have access to

**Figure 1.** *Map of Nigeria showing the six Hydrological Basin.*

*Application of Water Quality Index for the Assessment of Water from Different Sources… DOI: http://dx.doi.org/10.5772/intechopen.98696*


*NE: North East, NW: North West, NC: North Central, SE: South East, SW: South West, SS: South–South. Source: Extracted from Amakom [48].*

#### **Table 4.**

*Evaluation of regional access to water supply in Nigeria.*

improved water sources while 43% of the rural populations do not have ready access. Regionally, access to improved drinking water sources in the north central, north eastern and north western zones is 52.2%, 27.3%, 42.5%, respectively. Access to improved drinking water sources is 72.7% and 54.1% in the south western and south eastern zones of Nigeria, respectively. Thus, high disparity exists between the urban and rural populations regarding their access to good water. A similar disparity between the northern and southern regions of Nigeria is clearly shown as depicted in **Table 4**. It can be inferred from the table that the SW and NW zones and the urban areas have demonstrably higher access to a safe water supply. The problem of water pollution arising from petroleum oil exploration in the south tends to limit the availability of freshwater resources from the natural sources [46, 47]. In most parts of the Niger- Delta (SS) region of Nigeria, the major challenge for survival is the availability of good quality (potable) water free of environmental pollution and degradation. According to Raimi [46], the sources and percentage frequencies of water in the oil producing communities in the Central Senatorial District of the Bayelsa State is: rain (61%), rivers (13%), pipe-borne (33%) borehole (91%) and hand-dug well (3%). This distribution of water sources is similar in most cities in the other parts and zones in the country. Thus, it implies that the most frequently used water sources in Nigeria are borehole, rain water and pipe-borne water except in the rural areas where the major sources are hand dug wells and rivers.
