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2026-08-10Reclaimed Water Recharge into Groundwater Gets a "New Yardstick": GB/T 19772-2026 Expands Control Indicators to 118, Fortifying the Water Quality Safety Bottom Line
Recharging groundwater with reclaimed municipal wastewater is an important measure for alleviating China's water scarcity and reversing groundwater over-extraction, but the water quality safety of "reclaimed water entering the ground" has long been a focus of public concern. Recently, the State Administration for Market Regulation and the Standardization Administration of China officially issued GB/T 19772-2026 Urban Wastewater Reuse — Groundwater Recharge Water Quality, which will take effect on December 1, 2026. This is the first systematic revision since the standard was first published in 2005 — the number of control indicators has been substantially expanded from the original 73 to 118, and for the first time a whole-process monitoring system for "groundwater in the recharge zone" has been established, setting a stricter and more detailed "new yardstick" for safe reclaimed-water recharge into groundwater.
1. Why the Revision: From 39 to 93 Indicators, Standards Had to "Keep Pace"
The revision was not made "for the sake of change", but stemmed from the upgrading of upstream standards and the push of real-world demand. The Groundwater Quality Standard (GB/T 14848-2017), which is closely related to groundwater recharge water quality, had already expanded its control indicators from 39 to 93, adding 54 new ones. At the same time, extensive research and engineering practice on groundwater recharge with reclaimed water has accumulated in recent years, and the industry's awareness of managing risks such as emerging contaminants and pathogenic microorganisms has grown markedly.
Against this backdrop, the 2005 version of the standard, in use for twenty years, could no longer match current technical capabilities and regulatory requirements. The 2021 Guiding Opinions on Promoting Wastewater Resource Utilization explicitly called for strengthening related research and the development and revision of standards, and this revision is the on-the-ground response to that top-level deployment.
2. Core Changes: 118 Control Indicators, the Safety Gate Tightened Across the Board
The most central revision of the new standard focuses on optimizing the control indicators and their limits, following the fundamental principle that "groundwater recharge must not pollute groundwater", benchmarking against the Groundwater Quality Standard and the Environmental Quality Standard for Surface Water, and referencing relevant domestic and international standards.
Indicator count "expanded" to 118. Basic control indicators increased from 21 to 38, and optional control indicators increased from 52 to 70. Among these, sensory indicators such as "odor and taste" and "visible matter", as well as the "permanganate index", were newly added; more critically, 14 chemical and toxicological indicators — including iron, manganese, mercury, arsenic, lead and chloroform — were upgraded directly from "optional control indicators" to "basic control indicators" in the document, meaning these items changed from "optional" to "mandatory testing", significantly strengthening regulatory rigidity.
Optional control indicators "fill 32 gaps". The standard adds 32 new indicators, including metals such as aluminum and sodium, halogenated hydrocarbons such as dichloromethane and 1,2-dichloroethane, aromatics such as trichlorobenzene and styrene, and pesticides such as 2,4-D and carbofuran, bringing emerging and micropollutants into the monitoring scope and filling the technical blind spots of the old version.
Limits "finely tuned". The standard adjusts the limits of seven basic indicators, including turbidity, volatile phenols, COD, BOD5, total phosphorus, sulfide and nitrate; refines the category-specific limits of 14 basic indicators, such as heavy metals and organic toxicants, for the two different recharge methods of "surface infiltration" and "well injection"; and also revises the limits of five optional control indicators, including alkylmercury, nickel, barium, hexachlorobenzene and gross alpha radioactivity.
3. The 118 Key Indicators in Detail: Understanding "Mandatory" and "Optional" at a Glance
(1) Basic Control Indicators, 38 Items — "Mandatory Testing"
The following indicators must be tested and meet standards before recharge water leaves the plant, divided into five categories by attribute:
Sensory and physicochemical basics (11 items): color, turbidity, pH, odor and taste, visible matter, total hardness (as CaCO₃), total dissolved solids, sulfate, chloride, anionic surfactants, permanganate index (as O₂).
Comprehensive organic pollution indicators (8 items): chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD₅), petroleum hydrocarbons, animal and vegetable oils, volatile phenols (as phenol), cyanide, sulfide, fluoride.
Nutrients and nitrogen/phosphorus (4 items): ammonia nitrogen (as N), nitrate (as N), nitrite (as N), total phosphorus (as P).
Microorganisms (2 items): fecal coliforms, total coliforms.
Metals and toxicology — 14 items upgraded from "optional" to "mandatory" (14 items): iron, manganese, copper, zinc, mercury, arsenic, selenium, cadmium, chromium (hexavalent), lead, chloroform, carbon tetrachloride, benzene, toluene.
(2) Optional Control Indicators, 70 Items — "Optional Testing"
Beyond the basic indicators, these are tested selectively according to the hydrogeological conditions of the recharge zone, pollution source characteristics and other factors, comprising "38 retained/adjusted items + 32 newly added items":
The 32 newly added items (key "gap-filling"):
Metals (6 items): aluminum, sodium, antimony, cobalt, molybdenum, thallium;
Halogenated hydrocarbons (11 items): dichloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,2-dichloropropane, bromoform, vinyl chloride, 1,1-dichloroethylene, 1,2-dichloroethylene (total), trichlorobenzene (total), styrene;
Aromatics and polycyclic aromatic hydrocarbons (7 items): 2,4-dinitrotoluene, 2,6-dinitrotoluene, naphthalene, anthracene, fluoranthene, benzo(b)fluoranthene, polychlorinated biphenyls;
Pesticides (8 items): 2,4-D, carbofuran, aldicarb, dichlorvos, chlorpyrifos, chlorothalonil, atrazine, glyphosate.
The 38 items retained from the 2005 version with adjusted limits (partial list): alkylmercury (not detectable), nickel, beryllium, silver, barium, benzo(a)pyrene, formaldehyde, aniline, nitrobenzene, malathion, dimethoate, parathion, methyl parathion, pentachlorophenol, trichloroethylene, tetrachloroethylene, xylene (total), etc., covering multiple risk dimensions such as heavy metals, pesticides and organic toxicants. Among these, the limits for nickel, barium, hexachlorobenzene and gross alpha radioactivity were tightened simultaneously in this revision.
(3) Category-Specific Limits: "Two Yardsticks" for Surface Infiltration and Well Injection
| Indicator | Surface infiltration | Well injection |
|---|---|---|
| Turbidity (NTU) | ≤10 | ≤3 |
| Color (dilution factor) | ≤30 | ≤15 |
| Iron (mg/L) | ≤0.3 | ≤0.3 (stricter by category) |
| Ammonia nitrogen (mg/L) | ≤1.0 | ≤0.2 |
In addition, under the well injection method, recharge water must remain underground for more than 12 months before being abstracted for use, leaving sufficient buffer for the natural attenuation of pollutants.
(4) Reference Indicators, 32 Items — "Forward-Looking Observation Posts"
Based on the principle of forward-looking design, the standard adds 32 "reference indicators" and reference values in Appendix A, for preventing and tracking risk pollutants with large regional variation or uncertain hazards. These indicators are not yet mandatory, but reserve a data and observation window for future standard upgrades.
4. Upgraded Management: From "Managing Water" to "Managing the Whole Process"
In terms of technical requirements: the standard specifies that a reasonable recharge method should be selected based on a suitability assessment for groundwater recharge, the hydrogeological conditions of the recharge zone and the environmental situation, and that surface infiltration should be the preferred method; it specifies that if water quality may fluctuate due to changes in water source or treatment processes during recharge, recharge should be stopped immediately, and the basic and optional control indicators should be re-tested comprehensively and re-determined; and it clarifies the "underground residence time" requirement before recharge water is abstracted for use — under the well injection method, recharge water must remain underground for more than 12 months.
In terms of the monitoring system: the standard adds a dedicated chapter on "groundwater sampling and monitoring in the recharge zone", setting strict requirements for monitoring layout, sampling, monitoring frequency and online monitoring, extending regulatory oversight from the "reclaimed water outlet" to the "underground aquifer". At the same time, based on the principle of forward-looking design, it adds 32 "reference indicators" and reference values (Appendix A) for groundwater monitoring in the recharge zone, reserving "observation posts" for future standard upgrades.
5. Significance of Implementation: Safeguarding Wastewater Resource Recovery and Groundwater Safety
Recharging groundwater with reclaimed municipal wastewater is an important direction for wastewater resource utilization, which can both "replenish water" for over-extracted areas and absorb treated tailwater that meets standards. Once implemented, the standard will better regulate the whole process of reclaimed-water recharge into groundwater, promoting wastewater resource recovery while effectively safeguarding groundwater quality and human health in the recharge zone.
From an industry perspective, the implementation of the new standard will force upgrades in reclaimed water treatment processes — particularly releasing further technical demand for membrane treatment, advanced oxidation, and advanced nitrogen and phosphorus removal; the densification of the recharge-zone monitoring network will also drive growth in market segments such as online water quality monitoring and smart water management. For enterprises engaged in the construction and operation of wastewater treatment and water reuse facilities, proactively aligning processes and building monitoring capabilities against the 118 indicators is both a compliance requirement and an entry point to seize market opportunities.
The release of GB/T 19772-2026 marks a new stage in which reclaimed-water recharge into groundwater in China moves from "able to recharge" to "safe, regulated recharge". The door of the standard has opened, and the industry's actions should accelerate.
(This article was compiled based on the national standard interpretation materials for Urban Wastewater Reuse — Groundwater Recharge Water Quality issued by the Standards Technology Division of the National Standardization Administration on August 5, 2026. Standard number: GB/T 19772-2026, effective December 1, 2026. The indicator details are subject to the official text of the standard.)
