Swap the cartridge on a Zone 3 household filter every month (2026-07-20)

A household water filter in Zone 3 only protects a family as long as its cartridge is actually working, and a spent cartridge that keeps running looks the same as a fresh one from the outside. A scheduled monthly swap keeps the filtration real instead of theoretical. This is a quick, repeatable visit to a home that has invited it. Standard: WHO household water treatment guidance; SDG 6 (Clean Water and Sanitation) Proof: Photo of the new cartridge installed Method (WHO household water treatment guidance; SDG 6 (Clean Water and Sanitation)): 1. Confirm the host invites the visit and locate the filter unit. 2. Check the cartridge age against the replacement window. 3. Remove the spent cartridge and install a fresh one. 4. Flush the new cartridge for the recommended time. 5. Photograph the new cartridge in place and record the swap date. Done when: Photo of the new cartridge installed

Where

Invited home kitchen, Zona 3, Guatemala City 01003

Pay

$140 proposed

This packet is not funded yet, so this figure is a proposed price and not money waiting in escrow. If a buyer funds it, approved proof settles that price onchain. If nobody funds it, approved proof earns provable credit toward the work instead of cash. You see which before you claim, never after.

Proof

Photo of the new cartridge installed

This is exactly what gets it approved. Nothing settles without it.

Level

entry

Open until

2026-08-19

How this work is done

A documented method, so this packet comes out the same whoever does it. Typically 30–60 minutes. Method of record: EPA drinking-water sampling (3Ts / LCR first-draw where lead is in scope)

Bring

• GPS-capable phone
• test kit for each named analyte (nitrate/coliform/arsenic/lead as specified)
• clean sample bottle + label
• nitrile gloves
• camera

Steps

1. 1. Navigate to the sampling point; confirm GPS is inside the posting radius; record the waypoint.
2. 2. Photograph the tap or wellhead with a legible timestamp.
3. 3. If first-draw is required, sample after >=6h stagnation; if flushed, run the tap 2-3 minutes first, then sample.
4. 4. Fill the bottle without touching the inside; cap immediately.
5. 5. Run each test per kit instructions; wait the exact develop/incubation time; read and record every value with units.
6. 6. Record coliform as present/absent after the stated incubation window.
7. 7. Enter all readings, units, GPS, time, and photos into the proof record; sign it.

If it does not match the plan

• Nitrate > 10 mg/L -> tag 'exceeds EPA MCL'; advise no infant consumption pending certified-lab confirmation.
• Total coliform present -> advise disinfection + retest; recommend lab confirmation.
• Arsenic > 10 ppb or Lead > 15 ppb -> tag exceedance; recommend certified-lab confirmation before any consumption guidance.

What counts as done

• GPS waypoint recorded inside the posting radius
• Timestamped photo of the exact sampling point
• Each required analyte recorded with a numeric value + units (or present/absent)
• Sampling type (first-draw vs flushed) explicitly noted

Proof is measured against these, not judged by taste.