02 · Planning & Site Selection
Most pond failures are decided on paper, not in the ground. Spend your first weekends planning; it pays back for decades.
Where to put it
- Sunlight: Aim for 6+ hours of sun for good plant growth, but avoid all-day scorching sun if you want to limit algae. A mix of sun and partial shade is ideal.
- Away from trees: Deciduous trees drop leaves that rot into ammonia. Keep ponds clear of the drip line, or budget for netting each autumn.
- Level ground is easiest, but a slope can become a beautiful waterfall if you work with it.
- Visibility: Place it where you'll actually see and enjoy it — near a patio or a window.
- Utilities: Call before you dig. Locate buried electric, water, gas, and septic lines.
Watch out
Never site a pond above or beside a septic field or where runoff from fertilized lawns will flow in. Nutrient input is the #1 cause of chronic algae.
Size & depth: the minimums
Bigger and deeper is more stable. A small pond swings temperature and chemistry fast; a larger volume self-regulates.
| Goal | Minimum size | Minimum depth | Notes |
|---|---|---|---|
| Wildlife / frog pond | 2×3 m | 60 cm | Shallow shelves crucial for exit |
| Planted garden pond | 4×3 m | 80 cm | Allows hardy lilies to overwinter |
| Fish pond (goldfish) | 6×4 m | 100 cm | Depth prevents winter kill |
| Swimming pond | 30+ m² | 180 cm (swim zone) | Split swim + plant zones |
Regulations & safety
- Many regions require fencing or permits for ponds deeper than ~30–40 cm, especially near homes with children.
- Check homeowner association rules and local wetland / drainage ordinances.
- Electric for pumps must be GFCI-protected and ideally on a dedicated outdoor circuit.
Define your goals
Write down, in order of priority: wildlife, swimming, fish, aesthetics, low maintenance. Your answer reshapes every later decision — a koi pond and a frog pond are almost opposite builds.
Site assessment checklist
- Mark the pond outline with a garden hose or spray paint.
- Stand inside the outline and look up — how many trees overhang?
- Check for underground cables or pipes (call your utility locator).
- Test drainage: pour a bucket of water on the lowest point. Does it pool or drain within an hour?
- Measure distance to the nearest power outlet.
- Note the sun path across the day.
Common mistake
Building too close to trees. Even “small” trees drop roots that can puncture liners and leaves that fuel algae. Keep at least 3 m clearance from deciduous trees.