Taipei Tap Water Quality

Key indicators at all 26 sampling points

Units: total hardness, total alkalinity, TDS and chlorine in mg/L; pH has no unit.

Treated water at the 8 treatment plants and sources

Why do the lowlands and the Shilin/Beitou highlands differ so much? The plants on the Xindian River system (Zhitan, Changxing, Gongguan) draw surface water, and their treated water reads 27.5, 27.3 and 27.4 mg/L total hardness. The sources serving Shilin and Beitou (Sanjiaopu, Ding-Beitou, Lujiaokeng) are separate mountain sources, reading 139, 85.2 and 71.4 mg/L. The main reason is the source: water from mountain sources passes through rock and picks up more dissolved calcium and magnesium, so hardness and alkalinity are naturally higher. This is common for mountain groundwater in Taiwan and is not a result of any treatment choice by the Taipei Water Department; the same gap shows up at the supply-system sampling points in Shilin and Beitou.

Source: Taipei Water Department, treated water quality of each treatment plant (data.taipei) , data period 2025-07/2026-06. The full 71 items are in the machine-readable JSON.

What it means for coffee and tea

The SCA (Specialty Coffee Association) recommends brewing water with total hardness of 50–175, alkalinity of 40–75 and TDS of 75–250 mg/L. Across the 26 Taipei sampling points, total hardness is 26.7–60.7 and alkalinity is 22.2–43.3 mg/L, so most points are below the SCA lower limit. That is the data-based explanation for why Taipei tap water can make thin, sour coffee: with little calcium, magnesium and bicarbonate in the water, extraction and buffering are both weak.

Tea is the other way round. The reference range commonly used by Taiwanese tea sellers (not an official standard) is a TDS of about 50–150, soft water preferred. Taipei's TDS of 57–121 mg/L mostly falls in that range. A brewing-water calculator (in Chinese) is available for working out whether to blend in RO water.

FAQ

Is Taipei tap water soft or hard?

Across the 26 sampling points, total hardness runs from 26.7–60.7 mg/L as CaCO3. Most points fall in the WHO "soft" band (0–60); the highest reading (60.7) is just above that threshold. See the table below for each point.

Can I drink Taipei tap water straight from the tap?

This page does not make that claim. What the data shows is that every value in the published tables (25 items at 26 supply-system points, 71 items at 8 treatment plants and sources) is within the drinking water standard limits, which is a statement about the water leaving the plants and sampled in the supply system. Between there and your tap the water passes through pipes and, in many buildings, a rooftop tank, which the Taipei Water Department does not manage. The department's own recommendation is to boil water before drinking; see the data source page (in Chinese).

Does Taipei water need adjusting for coffee or tea?

Total hardness (26.7–60.7) and total alkalinity (22.2–43.3) at most sampling points are below the lower ends of the SCA recommendation for brewing water (hardness 50, alkalinity 40), so coffee can taste thin and sour. For tea, a commonly cited reference range among Taiwanese tea sellers (not an official standard) is a TDS of about 50–150 mg/L, and Taipei's TDS of 57–121 mostly falls inside it.

Does water quality differ between districts?

Yes, mainly in hardness and alkalinity. See the sampling-point table below: points served from the Xindian River system in the lowlands read differently from points in Shilin and Beitou, which have separate mountain sources. The treatment-plant table shows the same gap at the source.

How current is this data? Is it live?

It is not live. The tables are the annual averages published by the Taipei Water Department for 2025-07/2026-06 (25 items × 26 sampling points, 71 items × 8 treatment plants and sources). They are not a test report for your own tap; what reaches you also depends on how often your building's tank is cleaned and on the age and material of the pipes.

Where can I find full water quality data for other cities?

At this level of detail (sampling points and treatment plants), only Taipei publishes complete data. Other cities officially publish only a few items such as total hardness, so this is a single-page tool rather than a city-by-city series.