PAS 100 compost is compost produced to a recognised specification for composted materials. However, meeting PAS 100 and achieving “end-of-waste” status are related but different requirements. In England, the Compost Resource Framework replaced the old Compost Quality Protocol on 20 October 2025.
For compost producers, buyers and land managers, the practical questions are straightforward: what does certification demonstrate, when can compost be supplied as a product rather than waste, and which rules apply where it will be used?
This guide explains the distinctions, the tighter plastics requirements and the checks worth making before buying or supplying compost.
Updated 19 October 2026. This article replaces our earlier coverage of the Compost Quality Protocol. The detailed end-of-waste requirements differ between England, Wales, Scotland and Northern Ireland.
What Is PAS 100 Compost?
PAS 100 is the Publicly Available Specification for composted materials. The version identified by the Compost Certification Scheme is BSI PAS 100:2018.
The 2018 revision introduced additional quality controls, including requirements for a Safety and Quality Control System addressing hazards affecting compost quality and safety. It is a production and quality specification, rather than simply a description of what compost looks like.
See the Compost Certification Scheme's information on BSI PAS 100:2018 and its explanation of the 2018 quality-standard improvements.
When buying compost, ask for evidence covering the actual product being supplied. A general statement that a business “makes PAS 100 compost” is less useful than a valid certificate and documentation identifying the relevant compost grade.
PAS 100, Certification and End-of-Waste Status Are Different
| Term | What it means |
|---|---|
| PAS 100 | The specification for composted materials. |
| Compost Certification Scheme | The assurance scheme through which producers demonstrate compliance with the applicable specification, scheme rules and certification category. |
| End-of-waste framework | The regulator's conditions for recognising qualifying waste-derived compost as a non-waste product. |
| Customer specification | The additional requirements agreed for the intended application. |
The Compost Certification Scheme issues separate national conformity marks. These reflect compliance with PAS 100, scheme rules and the relevant national end-of-waste requirements.
Do not assume that a certificate or conformity mark for one nation automatically establishes product status everywhere else. Check the destination and the certification scope. The scheme explains this on its compost certification mark page.
It is also more accurate to describe compost as “certified to PAS 100” than to use the old article's phrase “PAS 100 accredited quality protocol”. The standard, certification arrangements and regulatory framework are separate parts of the system.
What Replaced the Compost Quality Protocol in England?
The Environment Agency replaced the Compost Quality Protocol with the Compost from Waste Resource Framework on 20 October 2025.
The Agency's review identified changes to approved inputs, plastics limits, certainty of use and the point at which end-of-waste requirements are met. This was more than a change of title.
The quality protocols review explains the replacement process. Its references to a planned summer 2026 review should not be treated as evidence that a further revision has already been completed.
The Main Requirements
Under England's framework, qualifying compost must:
- Use approved source-segregated biodegradable inputs.
- Be processed and stored in accordance with PAS 100.
- Meet the applicable plastics limit and agreed customer specifications.
- Need no further treatment beyond that allowed by the framework.
- Have a certain use and appropriate third-party certification.
The framework also requires incoming-waste records and outgoing-product documentation, retained for at least four years. Production-site waste controls remain relevant while waste is being received and treated; product status does not turn a composting operation into an unregulated activity.
The Lower Plastic Limit for Compost
The English framework sets a maximum plastic concentration of 0.06% by mass in air-dry compost, half the 0.12% limit stated in PAS 100.
The Compost Certification Scheme's lower-plastic-limit factsheet explains the reporting basis, including the greater-than-2mm fraction. This is not a claim that compliant compost contains no plastic particles of any size.
For producers, the practical priority is controlling contamination throughout the process rather than relying solely on a final screening step. Collection quality, acceptance checks and processing arrangements all deserve attention.
Our article on compost depackaging and contamination removal explores the processing side of that challenge.
England's Transitional Arrangement: RPS 317
The Environment Agency introduced Regulatory Position Statement 317 for certain certified compost and digestate that did not meet the new plastics limits.
The deadline to register its use was 20 April 2026 and has passed. Producers cannot now assume they can join that transition.
Eligible operators who registered in time must meet all its conditions, including process upgrades, supporting evidence and record keeping. Full resource-framework compliance is required by 20 October 2027, when the statement is scheduled to expire unless amended or withdrawn.
RPS 317 is an enforcement position, not a change to the underlying permit requirement or automatic end-of-waste status. Check the current RPS 317 conditions rather than relying on a general statement that there is a two-year grace period.
Does the Same Compost Framework Apply Across the UK?
No. The arrangements must be checked for the nation where compost will be supplied and used.
| Nation | Position to check |
|---|---|
| England | The Environment Agency's Compost Resource Framework and any applicable regulatory position statements. |
| Wales | Natural Resources Wales' compost end-of-waste guidance and applicable regulatory statements. |
| Scotland | SEPA's regulatory position for compost, together with the relevant certification requirements. |
| Northern Ireland | The Compost Quality Protocol and applicable Northern Ireland certification requirements. |
For Wales, NRW's compost end-of-waste guidance includes its own requirements, including the 0.06% plastics limit.
Wales also has Regulatory Statement 122 covering certain certified materials that do not meet the additional plastics limits. At the time of this update, it is valid until December 2026, when it is due for review. Its conditions and timing differ from England's RPS 317.
The Compost Certification Scheme's national conformity-mark guidance provides a useful starting point for checking the applicable certification category.
Storage and Genuine End Use Matter
England's framework limits product-batch storage to ten months and requires supporting orders, contracts or qualifying sales history. Certified stock with little prospect of use can remain or become waste.
For specific production-site storage circumstances involving missing records, consult RPS 358. This is a conditional enforcement position, not permission for unrestricted storage.
A practical stock-management system should connect each batch with its production date, test information, storage location and intended customer. That makes it easier to identify material approaching a storage limit and distinguish real demand from an assumption that a buyer will eventually appear.
Using Compost on Agricultural Land
For agricultural supply under England's framework, documents must tell customers to have and follow a nutrient management plan. Applications must not exceed soil and crop need; excess application can make the compost waste again.
Other requirements, including animal by-products legislation and the Farming Rules for Water where applicable, continue to apply.
For buyers, the sensible sequence is to establish the field's requirements first, then select a suitable product and application rate. The availability of inexpensive compost is not, by itself, evidence that a field needs it.
What Buyers Should Ask Before Ordering PAS 100 Compost
Use the following questions as a purchasing checklist:
- Does the supplier hold a valid certificate covering this product and grade?
- Does its certification cover end-of-waste supply into the destination nation?
- Which batch or production records identify the material being delivered?
- What analysis and product information will accompany it?
- Is its particle size and composition appropriate for the intended job?
- Have any additional customer requirements been agreed in writing?
- Is the quoted price for the product alone or does it include delivery and spreading?
Certification is useful assurance, but purchasing decisions still need to match a particular material to a particular use. A soil-improvement project, a landscaping contract and a growing-media formulation do not necessarily require the same specification.
Compostable Packaging Is a Separate Issue
A claim that packaging is compostable should not be treated as permission to put it into any garden-waste or food-waste collection.
Check the receiving service's acceptance policy before disposal. Where the destination is uncertain, ask the collector rather than assuming that a compostable label guarantees an available treatment route.
For the practical distinction, read our guide to recyclable and compostable packaging in commercial composting.
Frequently Asked Questions
What does PAS 100 stand for?
It is the Publicly Available Specification for composted materials. The Compost Certification Scheme identifies BSI PAS 100:2018 as the relevant specification.
Is PAS 100 the same as the Compost Quality Protocol?
No. PAS 100 is a specification. The former Quality Protocol addressed when qualifying compost ceased to be waste. England now uses the Compost Resource Framework for that purpose.
Is “PAS 100 certified” enough information when buying compost?
Ask for the certificate and check its scope, product grade and relevant national conformity mark. Also establish whether the compost suits your intended application.
Can I register for England's RPS 317 plastics transition now?
No. The published registration deadline was 20 April 2026. Operators already using it must continue to meet its conditions and check for amendments.
Is PAS 100 the standard for anaerobic digestate?
No. Compost and anaerobic digestate have separate specifications and certification arrangements. Digestate is associated with PAS 110; do not use a compost certificate as evidence of digestate compliance.
Does certification establish a fixed compost price?
No. Obtain quotations for the specified grade and quantity, including transport and any spreading service. Do not confuse a composting gate fee charged for accepting incoming waste with the selling price of finished compost.
From Waste Treatment to a Useful Compost Product
Our original article reported the development of a clearer route from biodegradable waste to marketable compost. That objective remains relevant, but the terminology and regulatory requirements have moved on.
For a current buying or production decision, check the specification, certification scope, destination nation's rules and intended use together. Those checks are more useful than relying on the words “PAS 100” alone.
Official Guidance and Further Reading
- Environment Agency: Compost from Waste Resource Framework.
- Environment Agency: waste quality protocols review.
- Compost Certification Scheme: PAS 100 information.
- Current Compost Certification Scheme rules and technical documents.
- National compost conformity marks.
[Publication and update history: First published on 15 March 2007 to report the launch of the Compost Quality Protocol. Updated in April 2018 and revised on 19 November 2019, including coverage of PAS 100:2018. Substantially updated on 19 October 2026 to explain England's replacement Compost Resource Framework, plastics limits, certification requirements and the different UK end-of-waste arrangements.]
