Periodic maintenance
See also: Time between maintenance: filter element replacement.
- Consumers anticipate the need for periodic device maintenance, accept the costs involved, and correctly service their devices in a timely manner when needed.
- Fast-moving consumer goods (FMCG) (liquids and tablets): monthly replacement interval.
- Filter elements and other consumables:
- Best: consumable elements should have a minimum replacement interval of at least one year.
- Better: consumable elements need to be replaced every five to six months.
- Good: consumable elements need to be replaced every three to four months.
Key indicators
- Periodic maintenance or replacement frequencies are acceptable to users.
- A reliable and nearby supply of consumables, product parts, and replacements as well as technicians for routine repair, maintenance, and problems.
- The need for maintenance or replacement components is clearly communicated to the user.
- Periodic maintenance is quick, simple (minimal number of steps), and requires little or no assistance.
- The ratio between purchase price and recurring costs is acceptable to consumers.
- Users are provided with a true estimate of operating costs.
- Ideally, users are offered means to dispose of, recycle, or return used components.
Notes and exceptions
- As maintenance indicators, flow limiters are preferred to shutoff devices, which may trigger product abandonment.
- Different consumer segments indicate different preferences for the ratio between purchase price and recurring costs.
- Limit the number of components that require periodic replacement or maintenance and ensure all maintenance items have the same replacement frequency (e.g., pre-filters and filter elements are replaced as a unit).
- Disposal of spent filter elements does not add risk of contact with toxins.
Supporting evidence
- PATH. Extended User Testing of Household Water Treatment and Storage Products in Andhra Pradesh, India: Final Study Report. Seattle, WA: PATH: 2010. Available at: http://www.path.org/publications/detail.php?i=1841.
- Reference Design Beta Prototype Test. PATH, unpublished data, 2010.
- Full list of supporting evidence and additional materials.

The device design should allow effective, local solutions if replacement parts are not readily available. Here, a family uses a piece of cloth instead of the original equipment manufacturer pre-filter. Photo: PATH.