EN ISO 17805:2026

• Abstract:

  This document specifies procedures for sampling, capture and preservation of environmental DNA (eDNA) in aquatic environments, stemming from organisms that are or have recently been present in a waterbody, have visited it or whose DNA has been introduced to the waterbody through some mechanism. This document also covers procedures for avoiding sample contamination and ensuring DNA quality, key properties of the filtering procedure and equipment and reporting standards. This document does not include the collection of eDNA from biofilms, sediments or similar sample types and does not cover sampling designs.

• Status: Not Published
• Publication Date: 14-Jul-2026
• ICS: 13.060.70 - Examination of biological properties of water
• Technical Committee: CEN/TC 230 - Water analysis
• Drafting Committee: CEN/TC 230/WG 28 - DNA and eDNA methods
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Start Date: 26-Jun-2026
• Due Date: 05-Jan-2027
• Completion Date: 26-Jun-2026
• Ref Project: kSIST FprEN ISO 17805:2026 - Water quality - Sampling, capture and preservation of environmental DNA from water (ISO/FDIS 17805:2026)

• Consolidated By: ISO 17805:2026 - Water quality — Sampling, capture and preservation of environmental DNA from water
• Effective Date: 12-Feb-2026
• Revises: EN 17805:2023 - Water quality - Sampling, capture and preservation of environmental DNA from water
• Effective Date: 20-Nov-2024

Overview

EN ISO 17805:2026 - Water quality: Sampling, capture and preservation of environmental DNA from water is an international standard developed by CEN and ISO. It establishes guidelines for sampling water to collect, capture, and preserve environmental DNA (eDNA) in aquatic environments. The standard covers critical procedures for avoiding contamination and maintaining DNA quality, outlines best practices for the use of equipment and preservatives, and specifies reporting requirements to support consistent, reliable results in eDNA-based water quality monitoring.

Appropriate sampling and preservation of eDNA are essential for aquatic biomonitoring, biodiversity assessment, and compliance with regulatory frameworks such as the European Union Water Framework Directive. This standard enables laboratories, research organizations, and regulatory bodies to minimize errors and ensure high-integrity data for downstream genetic analyses.

Key Topics

• eDNA Sampling Procedures: Guidance on optimal water sampling methods for collecting eDNA from organisms present in waterbodies, excluding sediments and biofilms.
• Prevention of Contamination: Detailed protocols for equipment cleaning, sample handling, and personnel hygiene to avoid cross-contamination.
• Filtration and Capture: Overview of filter types (enclosed, open, housed) and considerations for their use, including choice of pore size and materials to maximize DNA recovery and minimize sample loss.
• Sample Preservation: Procedures for immediate field preservation using freezing, drying, or chemical solutions (e.g., ethanol, Longmire’s solution) to halt DNA degradation.
• Equipment Requirements: Specifications for gloves, pumps, syringes, filter capsules, and storage containers suitable for eDNA work.
• Reporting Standards: Essential metadata to be recorded, such as sample location, environmental parameters, filter type, and preservation method, crucial for data reproducibility and interpretation.

Applications

EN ISO 17805:2026 has broad practical value across multiple sectors concerned with environmental management and molecular biodiversity monitoring:

• Biodiversity Assessment: Enables the detection and monitoring of aquatic species, including invasive, endangered, or cryptic organisms, by analyzing DNA from water samples without needing to capture live specimens.
• Regulatory Compliance: Assists in fulfilling national and international obligations for water quality assessment under environmental directives and agreements.
• Ecological Research: Facilitates consistent, comparable eDNA sampling methods for studies on aquatic ecosystem health, population dynamics, and community composition.
• Conservation Management: Provides standardized protocols for agencies and NGOs tasked with habitat monitoring, restoration, and impact assessment of water bodies.
• Early Warning Systems: Supports rapid detection of harmful species or pathogens, allowing for timely management actions.

Related Standards

EN ISO 17805:2026 is part of a suite of water quality standards and eDNA guidelines. Relevant standards that may be used in conjunction with this document include:

• EN ISO 7027-1:2016: Water quality - Quantitative determination of turbidity.
• EN 14011:2003, EN 14757:2005, EN 15460:2007: Standards for biological and ecological examinations of water.
• CEN/TR 17245:2018: Routine sampling of benthic diatoms for metabarcoding.
• Nagoya Protocol: International legal framework for access to genetic resources - compliance may be necessary before sampling.

Practical Value

By adhering to EN ISO 17805:2026, organizations and professionals enhance the reliability and comparability of eDNA data. The standard supports evidence-based environmental decision-making, enables international collaboration, and helps protect aquatic ecosystems by providing clear, replicable protocols for eDNA collection and preservation.

Keywords: water quality, environmental DNA, eDNA sampling, eDNA preservation, aquatic biomonitoring, EN ISO 17805, contamination prevention, filter types, preservative solutions, biodiversity assessment, water sampling standard.

SLOVENSKI STANDARD
oSIST prEN ISO 17805:2025
01-marec-2025
Kakovost vode - Vzorčenje, zbiranje in konzerviranje okoljske DNK iz vode
(ISO/DIS 17805:2025)
Water quality - Sampling, capture and preservation of environmental DNA from water
(ISO/DIS 17805:2025)
Wasserbeschaffenheit - Probenahme, Erfassung und Konservierung von Umwelt-DNA
aus Wasser (ISO/DIS 17805:2025)
Qualité de l’eau - Techniques de récolte et conservation de l’ADN environnemental à
partir d’échantillons d’eau (ISO/DIS 17805:2025)
Ta slovenski standard je istoveten z: prEN ISO 17805
ICS:
13.060.45 Preiskava vode na splošno Examination of water in
general
13.060.70 Preiskava bioloških lastnosti Examination of biological
vode properties of water
oSIST prEN ISO 17805:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 17805:2025
oSIST prEN ISO 17805:2025
DRAFT
International
Standard
ISO/DIS 17805.2
ISO/TC 147/SC 5
Water quality — Sampling, capture
Secretariat: DIN
and preservation of environmental
Voting begins on:
DNA from water
2025-02-04
ICS: 13.060.70
Voting terminates on:
2025-04-01
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
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TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
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BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
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RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 17805.2:2025(en)
oSIST prEN ISO 17805:2025
DRAFT
ISO/DIS 17805.2:2025(en)
International
Standard
ISO/DIS 17805.2
ISO/TC 147/SC 5
Water quality — Sampling, capture
Secretariat: DIN
and preservation of environmental
Voting begins on:
DNA from water
ICS: 13.060.70
Voting terminates on:
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
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be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
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Published in Switzerland Reference number
ISO/DIS 17805.2:2025(en)
ii
oSIST prEN ISO 17805:2025
ISO/DIS 17805.2:2025(en)
Contents Page
European foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Procedure . 3
5.1 General .3
5.2 Considerations prior to fieldwork .4
5.3 Equipment preparation prior to fieldwork .4
5.4 Sampling the eDNA from water .4
5.5 Preserving the sample .5
5.5.1 General .5
5.5.2 Preserving eDNA in enclosed filters .5
5.5.3 Preserving eDNA in open filters .5
5.5.4 Preserving eDNA in housed filters .6
6 Equipment . 6
7 Preservative solutions . 7
7.1 General .7
7.2 Examples of preservative solutions .8
8 Sampling report . 8
8.1 General .8
8.2 Sample identity and characteristics .8
8.3 Sampling site .8
8.4 Sampling conditions .8
8.5 Sampling .9
9 Avoiding sample contamination . . 9
9.1 General .9
9.2 Contamination avoidance .9
9.2.1 Contamination that originates from equipment .9
9.2.2 Contamination that originates from the person taking the samples .9
9.3 Sampling equipment decontamination procedure .10
9.3.1 General .10
9.3.2 Materials and equipment in direct contact with the water sample .10
9.3.3 Materials and equipment not in direct contact with the water sample .10
Annex A (informative) Filter types .11
Bibliography .12

iii
oSIST prEN ISO 17805:2025
ISO/DIS 17805.2:2025(en)
European foreword
This document (FprEN 17805:2022) has been prepared by Technical Committee CEN/TC 230 “Water
analysis”, the secretariat of which is held by DIN.
This document is currently submitted to the Formal Vote.
Any feedback and questions on this document should be directed to the users’ national standards body. A
complete listing of these bodies can be found on the CEN website.

iv
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ISO/DIS 17805.2:2025(en)
Introduction
WARNING — Persons using this document should be familiar with water sampling protocols to
assess biological diversity. This document does not purport to address all of the safety problems, if
any, associated with its use. It is the responsibility of the user to establish appropriate health and
safety practices.
Moreover, the need of notification, obtaining certificates or permits prior to sampling, depending
on national or international laws and regulations such as the Nagoya Protocol on Access to Genetic
Resources (https://www.cbd.int/abs/), needs to be considered.
The monitoring of organisms is key to the assessment of the status of aquatic ecosystems and is required by
national and international legislation such as the European Union Water Framework Directive (2000/60/
EC). A range of methods have been described how to monitor organisms in aquatic environments, leading to a
wide range of European standards (e.g. EN 14011:2003, EN 14757:2005, EN 15460:2007). These approaches,
however, necessitate the capture and/or collection of the organisms of interest, which can be a laborious
and time-consuming process.
The possibility to detect the presence of organisms and/or quantify relative abundance (e.g [6].) in aquatic
environments via the analysis of environmental DNA (eDNA) provides a novel means to monitor biodiversity
[7][8][9]
across a wide range of taxonomic groups, including microorganisms, plants and animals.( ) This
approach allows to examine organismic diversity without the need to directly isolate and capture organisms
and it is expected to play a key role for future biomonitoring aiming at temporally and spatially highly
[10] [11]
resolved species inventories. Albeit the power of the eDNA approach has been repeatedly reported,
[12]
there is a great need for standardizing the application of eDNA-based assessment of aquatic biodiversity.(
[13]
) Note, however, that eDNA-based biomonitoring currently does not allow to obtain certain population
parameters (e.g. individual size, sex) which can be obtained by traditional sampling techniques.
This document provides guidance how to sample and preserve eDNA from water samples, addressing the
first and crucial step for any further downstream eDNA-based analyses of biodiversity. A specific technical
report for the routine sampling of benthic diatoms from rivers and lakes adapted for metabarcoding analyses
is CEN/TR 17245:2018.
In this document, the following verbal forms are used to specify working procedures:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “may” indicates a permission;
— “can” indicates a possibility or a capability.

v
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oSIST prEN ISO 17805:2025
DRAFT International Standard ISO/DIS 17805.2:2025(en)
Water quality — Sampling, capture and preservation of
environmental DNA from water
1 Scope
This document specifies procedures for sampling, capture and preservation of environmental DNA (eDNA)
in aquatic environments, stemming from organisms that are or have recently been present in a waterbody,
have visited it or whose DNA has been introduced to the waterbody through some mechanism. This document
also covers procedures for avoiding sample contamination and ensuring DNA quality, key properties of the
filtering procedure and equipment and reporting standards.
This document does not include the collection of eDNA from biofilms, sediments or similar sample types, or
passive sampling methods, and does not cover sampling designs.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
cross-contamination
unintended transfer of any source and/or DNA from one sample to another sample
3.2
decontamination
procedure to remove any source and/or trace of DNA from material that might come into contact with the sample
3.3
enclosed filter
filtering system where the filter membrane is encapsulated and where the inflow and outflow can be closed
for transport and storage
Note 1 to entry: The eDNA contained on the filter is typically extracted without removing the membrane from the
filter capsule greatly reducing the risk of contamination of samples. See Figure A.1 C. in Annex A.
3.4
environmental DNA
eDNA
material from dead or living organisms including single-stranded (ss) and double-stranded (ds) DNA
fragment from nuclear and mitochondrial/plastid DNA of eukaryotes as well as plasmid chromosomal and
DNA of prokaryotes
Note 1 to entry: Subsuming DNA from various sources such as unicellular or small multicellular organisms or tissue
particles (e.g. shed cells, faeces) and gamets of multicellular organisms.

oSIST prEN ISO 17805:2025
ISO/DIS 17805.2:2025(en)
3.5
field equipment blank
a sample obtained from processing target DNA-free water (e.g. distilled water) through all the equipment
used and following all procedures involved in the eDNA sampling process to ensure that the equipment and
procedures do not introduce DNA contamination
3.6
housed filter
filtering systems in which a filter membrane is protected within a solid housing during the filtration process,
which is opened subsequently to remove the filter membrane for further processing
Note 1 to entry: The filters are removed from the housing for eDNA extraction. The housing can be opened and the
filter removed for preservation and later processing. See Figure A.1 B. in Annex A.
3.7
lysis buffer
buffer solution to preserve the DNA present in the sample and to lyse/open cells as a first step of the DNA
extraction
3.8
internal positive control
IPC
quantified amount of synthetic or natural DNA containing a PCR-amplifiable sequence that will not naturally
occur in the sample to distinguish types of negative results (no target sequence vs. PCR inhibition)
Note 1 to entry: The IPC can be added to the sample or the preservation/lysis buffer at a known concentration to
verify the efficiencies of DNA preservation, DNA extraction, DNA amplification and DNA identification.
3.9
open filter
filtering system including vacuum filtration units (laboratory) and filtration backpacks (field) from which
the filter membrane has to be removed with tweezers for further processing
Note 1 to entry: See Figure A.1 A. in Annex A
3.10
pre-filter
filter membrane, mesh or hose strainer with a larger pore-size than the main filter membrane (used for
capturing the eDNA) through which water is passed first to remove larger particles of sediment, plant
material or algae to increase the volume of water that can be filtered before saturation of the main filter
3.11
sample contamination
process by which exogenous DNA is unintentionally introduced to the sample
Note 1 to entry: DNA that is already present in the water before the eDNA sampling was undertaken is not considered
as contamination.
3.12
target DNA
any source and/or trace of DNA from the surveyed species/taxa
3.13
enclosed filter
filtering systems in which a filter membrane is protected within a solid housing during filtration and further
processing steps, e.g. lysis; it is not opened, minimizing sample contamination
Note 1 to entry: See Figure A.1 C. in Annex A

oSIST prEN ISO 17805:2025
ISO/DIS 17805.2:2025(en)
4 Principle
A representative water sample from the surveyed water body is sampled according to an appropriate
sampling design to capture and separate eDNA from the water sample. During the whole procedure cross-
contamination and sample contamination are avoided and eDNA integrity is guaranteed.
An overview on the key steps and considerations for the sampling, capture, and preservation of eDNA from
water in Figure 1.
NOTE Numbers in parentheses refer to the respective clause/subclause.
Figure 1 — Key steps and considerations for the eDNA water sampling process
5 Procedure
5.1 General
Water should be sampled to capture and separate eDNA via filtration or other processes. The probability of
obtaining eDNA from the targeted organism(s) is positively correlated with:
— the number of samples per waterbody;

oSIST prEN ISO 17805:2025
ISO/DIS 17805.2:2025(en)
— the spatial representativeness of the samples;
— the volume of water filtered;
— the optimum sampling time point/season with regard to the organism(s) eDNA shedding rates,
[15][16]
abundances (also of non-target organisms) including spawning time,( ) metabolic activity and
locomotion.
5.2 Considerations prior to fieldwork
Depending on the different applications/goals of each eDNA survey, the most appropriate sampling conditions
and design shall be assessed based on case-by-case evidence to obtain water samples representative of the
water body and the organisms being monitored. These might include hydrological, meteorological, seasonal/
temporal and biological/ecological and physiological variation.
This is particularly important in lentic (non-flowing) water bodies since eDNA is often unevenly distributed
when the water is not well mixed. Representative sampling can be achieved by combining subsamples
collected at different points in the water body, or alternatively by continuous sampling systems that move
across the water body while drawing up water. When surveying deep water bodies and targeting deep water
dwelling organisms, it may be necessary to sample water from depth.
To maximize the probability of capturing target DNA, the following shall be considered when planning
where and when to collect samples and subsamples:
1) Features of the water body, including its size, depth, flow, stratification and the distribution of
microhabitats as well as inlets/outlets of the waterbody. If the study requires separate analyses of
subsamples (for example biota in different depth layers), new or clean collection vessels shall be used
for each subsample.
2) Biology of all target taxa, including habitat preferences and lifecycle. Detection probability for individual
species can be increased by timing sampling to coincide with times of intense activity (e.g. spawning).
Temporal variations in the amounts of released eDNA by the target species needs to be considered. It is
also important to consider whether target taxa are likely to be present in the water body at the time of
sampling, especially in the case of amphibious or (diurnally) migratory species.
5.3 Equipment preparation prior to fieldwork
Prior to fieldwork a sufficient number of collecting vessels and equipment shall be cleaned to avoid
contamination (for detailed instruction see 9).
5.4 Sampling the eDNA from water
Various systems are used for sampling and filtering water. Some involve initially gathering water into a
collecting vessel where it is mixed and then filtered subsequently; other systems filter the water directly as
it is drawn up from the water body. When the water is not fil
...