- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 12 Oct 2020
The ‘water table’ is the below-ground level that marks the transition between ground that is saturated with water and ground that is not saturated. The upper, unsaturated level, is known as the 'capillary fringe' or 'zone of aeration'. The lower, saturated level, is known as the 'zone of saturation'. An aquifer is a pocket of water that is found below the water table.
As water moves down from the surface it filters through sediments and rocks and causes the water table to fluctuate. The water table typically follows the topography of the above-ground land, but sometimes intersects with the land surface, which may be evident from the presence of spring or oasis.
The level of the water table is influenced by:
- Geology: Heavy, dense rocks are capable of holding less water than light, porous rocks.
- Weather: which is why it tends to fluctuate seasonally.
- Extraction: for industrial purposes, drinking water and so on.
- The way land is used: it is common for urban areas to have predominantly impervious surfaces such as roads, car parks and public spaces, and these prevent the seepage of water into the ground. Instead it becomes run off, and the water table can dip as a result.
The SuDS Manual (C753), published by CIRIA in 2015 defines the water table as: 'The point where the surface of groundwater can be detected. The water table may change with the seasons and with annual rainfall.'
 Related articles on Designing Buildings Wiki
Featured articles and news
Training reflects updated guidance in BSRIA BG 29/2021.
Complete list of 2021 winners now available.
Recognising past and present role models for the future.
So why not write something?
LETI publishes guidance for energy efficient home retrofits.
Predictions about adequate post-pandemic IAQ in non-domestic buildings.
Government publishes plans to 'build back greener'.
The contentious nature of claims associated with cladding, fire safety and EWS1 forms.
ECA comments on low-carbon heating systems initiative and Heat and Buildings Strategy.