Probably Stolen water purification: grades, filters and tablets

How do you purify water?

Match the treatment to the contamination. The Water Trading Manual says tablets remove much of the microbial contamination and some chemical contamination, while a pitcher filter removes impurities, microplastics and organic waste. Combining them can improve a batch, but the result depends on the water you started with.

Treatment	What the game manual says it removes	Limitation
Water Purification Tablets	Large amounts of microbial contamination; some chemical contamination	Does not cover every contaminant
Water Filter installed in a pitcher	Impurities, microplastics and organic waste as water is poured in	Has limited durability
Dedicated Water Purifier with suitable modules	Used to reach higher purity	The manual does not provide a complete module-to-contaminant matrix

Start by testing the batch, choose a treatment, then test again. This is a practical way to apply the manual’s rules, not a claim that we have measured every treatment combination. The item and price reference helps identify the equipment; its base values are not guaranteed shop quotes.

What are the six water grades?

The manual divides water into six named grades, from Gutterflow to Pure Water. Read the purity result rather than trusting a seller’s label. Its printed ranges share boundary values, so this table preserves those ranges without claiming which category the game’s code assigns at an exact cutoff.

Grade	Range printed in the manual	Description in the game
Pure Water	99.9%+	Used in sensitive settings such as hospitals and laboratories
High-Quality	99%–99.9%	Described as safe for drinking, cooking and household use
Basewater	98%–99%	Lower Levels standard; the manual cautions against prolonged use
Ghostwater	96%–98%	Common in farming and industry; unsafe to drink unfiltered
Rustwater	90%–96%	Dangerous to drink and unsuitable for farming
Gutterflow	90% and below, printed as “90%-”	Heavily contaminated and toxic

These are the game’s fictional water categories. Ghostwater can look like higher-grade water, so appearance alone does not establish purity. The manual identifies Rustwater and Gutterflow as visually distinguishable.

Why does purification stop raising purity?

A treatment stops helping when the remaining contaminants are outside its target types. The manual explicitly describes this plateau. If repeated applications do not raise purity, change the treatment rather than assuming more of the same consumable will eventually produce Pure Water. The remaining contamination matters as much as the overall percentage.

The manual says tablets plus a filter may reach Ghostwater or Basewater depending on starting purity. It recommends a dedicated purifier with properly fitted modules for higher grades. That is guidance, not a guaranteed output recipe. We do not yet have a verified module matrix or output-per-cycle table.

How do you avoid wasting filters or buying mislabeled water?

Use a Water Testing Strip to check a batch and avoid relying on its label. The manual warns that basic treatment of Gutterflow wears filters rapidly. Before spending supplies, establish the starting purity and decide whether the equipment you have addresses the contamination left in that batch.

A useful first-batch checklist is:

1. Test the water before purchase or use.
2. Fit the filter inside a pitcher before pouring water through it.
3. Compare the test result after treatment.
4. Stop repeating an ineffective treatment.
5. Reserve a claim of higher-grade output for water you have actually tested.

For the surrounding shop routine, start with the beginner guide.

If your start menu offers Water Merchant, compare its testing and purification equipment in the starting-scenarios guide before choosing a run.

Which version and sources does this guide use?

This guide summarizes the game’s Water Trading Manual from Demo version 049-Rev5-L, Steam build 25382790. We checked the official English and Chinese localization text extracted from that build. It explains the documented mechanics; it does not report a played test run or a measured purification-profit experiment.