The TerraClear Ceramic Water Purifier (CWP) consists of a pot-shaped ceramic filter element set in a plastic receptacle tank, with a lid and spigot to protect filtered water from recontamination. Ceramic filtration uses porous, fired clay to filter microbes and other contaminants from drinking water: raw water seeps through the ceramic element by gravity, producing potable water at a rate of 1.7 to 3.5 liters per hour.

The CWP can filter up to 55 liters per day and store up to 36 liters of safe water in the receptacle tank. Maintenance consists of scrubbing the ceramic element to unclog pores and washing the receptacle tank to prevent bacterial growth — the filter is fed entirely by gravity, and the replaceable spigot is its only moving part.

The TerraClear Ceramic Water Purifier (CWP) is a zero-emissions, point-of-use ceramic water purification system. The product consists of a pot-shaped ceramic filter element set in a plastic receptacle tank with a lid and spigot to protect filtered water from recontamination.

Ceramic filtration is the use of porous ceramic (fired clay) to filter microbes or other contaminants from drinking water. Raw water seeps through the ceramic filter element by gravity at a post-production rate of 1.7 to 3.5 liters per hour, producing potable water.

The CWP can filter up to 55 liters per day and store up to 36 liters of safe water in the receptacle tank. Maintenance consists of scrubbing the ceramic filter element to unclog pores and washing the receptacle tank to prevent bacterial growth. The product is a low-technology solution to households' lack of access to safe water: the filter is fed by gravity, and the replaceable spigot is the only moving part.

The filters themselves are kiln-fired clay impregnated with colloidal silver. TerraClear manufactures the filter elements at a purpose-built factory near Pakse, Lao PDR. Locally sourced clay and rice husks are ground to a specific size and mixed at precise levels. This precise ceramic mixture of clay and rice husks is then molded into pots and fired in a kiln. During firing, the rice husk burns away and creates the extremely small pores which, due to size exclusion, act as physical barriers to micro-organisms — making the filter effective at removing bacteria, protozoa, helminths, turbidity, and other suspended solids. After firing, the filters are brushed with colloidal silver, infusing the clay pores to provide a permanent, secondary defense, which — when used correctly — removes over 99% of bacteria^{1 2 3 4}.

The ceramic filter element has a potential useful life of 7 years or longer⁵. Lifespan mainly depends on the quality of the input water and the care taken to avoid breakage.

Water treated by a CWP has no significant taste issues. CWPs have functional stability, meaning they have only one moving part (the spigot) and require no external energy source (such as a UV lamp) or consumables (such as chlorine packets, or media that must be regenerated or replaced).

Government certification

Several ministries of the Government of Lao PDR have certified the TerraClear CWP. Testing and certification was provided by the Ministry of Food and Drug, providing a "Pass" for the following tested parameters: hardness, pH, total coliforms, E. coli, and fecal coliforms⁶. The Ministry of Health has also endorsed the product following a 2012 study of the filters, which tested for E. coli and total coliforms from a number of water sources — including shallow well, spring water/mountain source, river water, borehole, town water, and pond water. The certificate from the Ministry of Health states that "the water filter is appropriate for every water situation throughout the country"⁷.

TerraClear filters are regularly sold with refillable 12-liter bottles, which can be used to collect untreated water and positioned on the system to automatically flow into the filter. Stands are also produced and regularly purchased by end users for convenience and hygiene. A pictorial instruction sticker is fixed to the side of each CWP unit, along with contact details to facilitate questions and replacements.

¹ Roberts M (2003) Ceramic Water Purifier – Cambodia Field Tests, IDE Cambodia, Phnom Penh, p 4–6.

² Brown J, Sobsey M, and Proum S (2007) Improving Household Drinking Water Quality: Use of Ceramic Water Filters in Cambodia, WSP Field Note, World Bank Water and Sanitation Program, Phnom Penh, p 22–32.

³ Bloem SC (2008) Silver Impregnated Ceramic Water Filter – Flowrate versus the removal efficiency of pathogens, Delft University of Technology, Faculty of Applied Sciences, Delft, Netherlands.

⁴ Phimmason, B, PhD (2011) Experiment Using Water Filter Ceramic to Decrease Coliform Bacteria in Water, Ministry of Health, National Centre for Environmental Health and Water Supply, Vientiane, Lao PDR.

⁵ Lantagne, D (2001) Investigation of the Potters for Peace Colloidal Silver Impregnated Ceramic Filter – Report 1: Intrinsic Effectiveness, p 58. Available online.

⁶ Government of Lao PDR (2011) Certificate of Testing for TerraClear CWP, Ministry of Health, Drug and Food Testing Centre, Vientiane, Lao PDR.

⁷ Government of Lao PDR (2012) Certificate of Testing for TerraClear CWP, Ministry of Health, National Centre for Environmental Health and Water Supply, Vientiane, Lao PDR.

Ceramic water filters need to be produced with careful quality control to ensure they can remove contaminants and provide a useful quantity of water for a family. Ceramic is naturally porous, but to increase the porosity to a precise level, ground organic materials are added. In Laos, the local organic material is sticky rice husk. Specially selected terracotta clay is ground into a powder, and these two main ingredients are mixed with water to form the moldable blocks that become a filter.

Mechanical pressing in a mold makes the traditional pot shape; staff then smooth and clean the surface.

Once these shaped pots are dried, they enter a gas-fired kiln, where a firing technician heats them along a prescribed temperature curve over a 12-hour period. This burns out the rice husk, locks in the network of pores, and forms the ceramic.

These ceramic filters undergo a visual, audible, and two types of hydrology evaluations. Filters with a uniform network of correctly sized pores pass on to the next stage, and some from each group are taken to our on-site laboratory for confirmed bacteriological testing.

Passing filters are then infused with colloidal silver suspended in water. This silver water absorbs throughout the pore network, inside and out; as the water evaporates, silver is left coating the pores as a permanent bactericide.

After a final QA check, filters are paired with a food-grade 36-liter plastic receptacle, tap, filter fitting ring, and lid. These help prevent recontamination, getting clean water as close to the cup as possible. Stands and filling bottles make the sets complete, and they're sent by truck and motorbike around the country.

A filter that pays for itself twice.

Drinking untreated water from contaminated sources often results in serious illness, and in many cases death. Boiling drinking water before consumption reduces that risk — but it also puts serious pressure on already-diminishing Lao forests.

Households that use a TerraClear filter typically reduce or eliminate boiling water for drinking. Families no longer spend long hours collecting fuel wood, or making or buying charcoal, to boil drinking water. Because the filter needs no energy source to work, each one in use reduces the strain on local forest resources and reduces greenhouse gas emissions.

Based on these environmental and social benefits, TerraClear has registered as a carbon project through the Gold Standard Foundation. We currently have two Carbon Emission Reduction projects — one existing project with credits issued since 2014, and a new project currently in preparation for registration.

TerraClear Safe Drinking Water in Laos — GS23624

This project underwent stakeholder consultation from April 12, 2026 to May 12, 2026. Although the official open period has closed, TerraClear always welcomes feedback, concerns, or grievances through any of the following channels:

In person

Directly in the grievance book located at the company office:
TerraClear Production, Km 10, Road 13 South, Pakse
Lomsakneua Village, Bachiang District, Champasak Province, Lao PDR

Via contact details

• Email: info@terraclear.org
• Contact form: terraclear.org/contact
• Phone: +856 (0)20 5637 4888

Via the Gold Standard

(once the project documents are published on their platform)

• Website: www.goldstandard.org
• Email: info@goldstandard.org

At the request of participants at the in-person and online stakeholder meeting on May 13, 2026, we're providing the stakeholder consultation presentation for download in both English and Lao:

• Stakeholder Consultation Presentation (English)
• Stakeholder Consultation Presentation (Lao)

Please use the form below to submit an application.

TerraClear Production provides equal opportunities for employment for all qualified persons and does not discriminate.