Pond Seepage Loss & Where Your Water Goes
Loses seepage
Enter your pond area and seepage rate to get the daily seepage loss, the total loss over a period in cubic metres and litres, and see what lining would save.
Describe your farm pond
Next: if 300 m³ over 30 days is excessive, line the pond (HDPE/clay/bentonite) — a good liner can cut seepage by 80–95%.
Daily loss = area × seepage depth. Seepage adds to evaporation; measured rates fall as fine sediment self-seals the bed over time.
Pond seepage — key facts
- Daily loss
- area × seepage rate
- Total loss
- daily loss × days
- Clay bed
- ≈ 2–5 mm/day
- Loam bed
- ≈ 10–25 mm/day
- Sandy bed
- ≈ 50+ mm/day
- 1 mm over 1 m²
- = 1 litre
- Cut it with
- clay / LDPE / bentonite lining
- Privacy
- Runs in your browser; nothing uploaded
An unlined pond leaks every single day
A farm pond is only as useful as the water it holds onto. On permeable soil, water escapes through the bed and banks by seepage — quietly, continuously, day after day — and a pond filled in the monsoon can lose a large share of its store before the dry season is over. Seepage is loss = pond area × seepage rate, and because it compounds over the days you store water, even a modest daily rate adds up to a big total.
This tool estimates your daily seepage loss and the total loss over a period, in cubic metres and litres, and lets you compare rates to value lining with clay, LDPE or bentonite. Use it to decide whether a liner pays for itself. Pair it with the Farm Pond Lining, Farm Pond and Pond Evaporation Loss tools to design a pond that actually keeps your water.
See the daily drain
Area times seepage rate is what you lose each day.
Watch it compound
Total loss over the storage period is the real cost.
Value the liner
Compare rates to size what lining would save.
Plan your storage
Know how much usable water you'll actually keep.
Frequently Asked Questions
What is pond seepage?+
Seepage is the water that escapes a farm pond through its bed and banks into the surrounding soil, separate from evaporation off the surface. In an unlined pond on permeable soil it can be the single biggest loss, draining a useful share of your stored water before you ever pump it. Estimating it tells you whether lining is worth the investment.
How is seepage loss calculated?+
Seepage loss = pond wetted area × seepage rate. The rate is a depth of water lost per day (mm/day), so multiplying by the area gives a volume per day. Over a storage period it compounds: total loss = daily loss × days. This tool does both, in cubic metres and litres, from your area and rate.
What is a typical seepage rate?+
It depends entirely on the soil. Tight clay beds may lose only 2–5 mm/day, loams perhaps 10–25 mm/day, and sandy or fractured beds 50 mm/day or more. If you don't know your rate, measure the water-level drop over a still, cloudy day (to minimise evaporation) and subtract estimated evaporation, or use a soil-based estimate.
How does lining cut seepage?+
A liner puts a low-permeability barrier between the stored water and the soil. Compacted clay or bentonite reduces the bed's permeability; an LDPE or HDPE geomembrane nearly eliminates seepage. Cutting the rate from, say, 30 mm/day to 2 mm/day saves the bulk of the loss — the tool lets you compare rates to value the saving.
How do I turn the loss into litres?+
One cubic metre is 1,000 litres, and one millimetre of depth over one square metre is one litre. So a pond of 1,000 m² losing 20 mm/day loses 20 m³ = 20,000 litres a day. The tool reports the daily and total loss in both m³ and litres so you can relate it to your irrigation needs.
Is seepage the same as evaporation?+
No. Evaporation is water leaving the surface as vapour and depends on weather and surface area; seepage is liquid water leaking through the bed and banks and depends on soil permeability and wetted area. Both reduce stored water — use this tool for seepage and the Pond Evaporation Loss tool for the surface loss.
How long does seepage loss compound?+
For as long as you store water. A pond filled in the monsoon and drawn down through a dry season loses water every single day to seepage, so a modest daily rate becomes a large total over weeks and months. The tool's total-loss output over your chosen number of days makes that cumulative drain visible.
When is lining worth it?+
Compare the total water saved over the storage period against the lining cost and the value of that water for irrigation. On permeable soils with high seepage and scarce water, lining usually pays back quickly; on tight clay with low seepage it may not. The tool quantifies the water at stake so you can run that comparison.
Are these figures exact?+
They're sound planning estimates from area × rate × days. Real seepage varies with water depth, soil heterogeneity, the water table and how well a liner is installed, and the rate often changes as fine sediment seals the bed over time. Use the tool to size the loss and the lining benefit, then verify with a field drawdown test.