Water table
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.
- Vegetation.
- Snowmelt.
- 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.'
[edit] Related articles on Designing Buildings
Featured articles and news
Retrofit 25 – What's Stopping Us?
Exhibition Opens at The Building Centre.
Types of work to existing buildings
A simple circular economy wiki breakdown with further links.
A threat to the creativity that makes London special.
How can digital twins boost profitability within construction?
The smart construction dashboard, as-built data and site changes forming an accurate digital twin.
Unlocking surplus public defence land and more to speed up the delivery of housing.
The Planning and Infrastructure Bill
An outline of the bill with a mix of reactions on potential impacts from IHBC, CIEEM, CIC, ACE and EIC.
Farnborough College Unveils its Half-house for Sustainable Construction Training.
Spring Statement 2025 with reactions from industry
Confirming previously announced funding, and welfare changes amid adjusted growth forecast.
Scottish Government responds to Grenfell report
As fund for unsafe cladding assessments is launched.
CLC and BSR process map for HRB approvals
One of the initial outputs of their weekly BSR meetings.
Architects Academy at an insulation manufacturing facility
Programme of technical engagement for aspiring designers.
Building Safety Levy technical consultation response
Details of the planned levy now due in 2026.
Great British Energy install solar on school and NHS sites
200 schools and 200 NHS sites to get solar systems, as first project of the newly formed government initiative.
600 million for 60,000 more skilled construction workers
Announced by Treasury ahead of the Spring Statement.
The restoration of the novelist’s birthplace in Eastwood.
Life Critical Fire Safety External Wall System LCFS EWS
Breaking down what is meant by this now often used term.
PAC report on the Remediation of Dangerous Cladding
Recommendations on workforce, transparency, support, insurance, funding, fraud and mismanagement.
New towns, expanded settlements and housing delivery
Modular inquiry asks if new towns and expanded settlements are an effective means of delivering housing.