Fourth Layer – Additional Charcoal:
Add another layer of charcoal to increase purification efficiency and provide an extra safety barrier.
Fifth Layer – Top Sand Layer:
Place another layer of clean sand on top. This prevents charcoal from shifting and acts as the first filter for finer debris.
Sixth Layer – Gravel or Small Pebbles:
Top everything with a layer of clean gravel. This blocks leaves, twigs, and larger debris from entering the filter, while helping to evenly distribute the water flow over the sand layer.
diy water filter bottle layers
4. Testing Your Filter
Place the top half of the bottle (now the filter) upside down into the bottom half or another clean container.
Pour dirty water slowly over the gravel layer and watch as it travels through each stage of filtration. The cotton at the bottom will catch the last bits of sediment before the water drips out into the container below.
While the filtered water may not look like commercial bottled water, it should be noticeably clearer and free from most visible debris.
