A bore log is the written record of what a borehole found: soil type at each depth, colour, consistency, samples taken and where water appeared. The water table reading tells you how deep groundwater sits under your plot. Together they shape basement design, foundation depth, dewatering during excavation and where you can put an underground water tank.
What is included
| Item | What it shows |
|---|---|
| Borehole location plan | Where each hole was drilled on your plot |
| Bore log | Soil layers with depth, description, sample points and field test results |
| Groundwater level | Depth at which water was first struck and the level after it settled |
| Date and weather note | When readings were taken, since levels can move with season and nearby pumping |
| Engineer's comments | What the layers and water level mean for excavation and foundations |
A bore log is usually part of a full soil investigation. Some owners ask only for logs and water readings when the engineer already has strength data for the area.
When you need it
- Basements. The LDA Building and Zoning Regulations say parking basements can be built "according to the soil conditions/water table in the particular area", and require a separate sanction stage for the basement excavation plan including retaining structure design (LDA regulations). For plots up to 1 kanal, the same rules allow one basement up to 12 feet deep from road level. A high water table affects waterproofing, uplift and whether you need pumping during digging.
- Underground water tanks and septic tanks, where water pressure from outside can push on walls and floors.
- Deep or unusual foundations.
- Plots near canals, drains or low ground, or where neighbours report damp basements.
- Adding floors or a basement under an existing house.
Step-by-step process
- Brief from your engineer. Number of holes, target depth and whether repeat water readings are wanted.
- Quotes from labs on that brief.
- Site access. Clear space for the rig and mark buried services.
- Drilling. The driller logs layers as they go and takes samples.
- Water reading. Water depth is noted when struck and again after it has had time to settle.
- Optional repeat readings. If your engineer wants seasonal data, the lab returns for more readings.
- Report. Signed bore logs and water levels, sent to your structural engineer and architect.
Approvals and documents
Under LDA rules, basement plans are sanctioned as a separate stage, so the excavation and retaining design your engineer prepares will rest on this data. DHA and private societies have their own building control rules; ask their office what they want with a basement submission. Keep the bore log with your structural calculations.
What affects the cost
No prices here; they vary by lab and site. Get written quotes. Cost depends on:
- Number and depth of boreholes
- Hard layers or water inflow that slow drilling
- Whether lab tests on samples are added
- Repeat visits for water readings
- Site access and distance
- Report urgency
Questions to ask the lab
- How will you record the water level: when struck, after settling, or both?
- How long will you wait before taking the settled reading?
- Can you come back for a repeat reading, and what does that cost?
- Who signs the bore logs, and are they PEC-registered?
- Will the log describe each layer and show sample depths?
Red flags
- A water level stated without a date or time.
- Logs that show the same layer description from top to bottom on ground known to vary.
- A lab that offers a water table figure "for the area" without drilling your plot.
- No engineer's signature or name.
- Advice to skip waterproofing or dewatering planning without data.
FAQs
Does the water table in Lahore change through the year? Groundwater levels can move with season, rainfall and pumping nearby. That is why the reading date matters and why some engineers ask for repeat readings.
Can I build a basement if water is shallow? Possibly, with the right design, waterproofing and excavation method. This is a decision for your structural engineer based on the bore log.
Is a bore log the same as a tube well drilling record? No. A tube well driller's notes are not an engineering bore log. Ask for logs prepared by a testing lab under an engineer.
How deep should the borehole go? Your structural engineer sets the depth based on the foundation type and building load.