The short answer
To get a Japanese knotweed survey, book a PCA-accredited invasive weed specialist who will inspect the property, confirm the plant, assess the risk under the 2022 RICS framework and give you a written report. Expect to pay roughly £150–£350 for the survey and report. That report is the document lenders and solicitors rely on, and it sets out whether a treatment programme or excavation is needed next.
If you have spotted knotweed — or a lender, solicitor or buyer has raised it — the single most useful thing you can do is commission a specialist survey. It turns uncertainty into a documented position: what the plant is, how far it has spread, the risk it poses, and what should be done. This page explains exactly what a survey includes, what it costs, and how to take the next step.
Booking a survey at a glance
- Cost £150–£350 for survey and report
- Who to book A PCA-accredited invasive weed specialist
- On site About 30–60 minutes
- Report A few working days, with a RICS risk category
- Then A costed treatment or removal plan if needed
What’s included in a survey
A proper survey delivers four things: identification, extent, risk and recommendation. The specialist confirms the plant is genuinely Japanese knotweed, maps how far it has spread (including any growth crossing a boundary), assesses the risk to the building and neighbouring land under the 2022 RICS guidance, and recommends what to do — monitoring, a herbicide programme or excavation.
- On-site inspection of the garden and accessible boundaries.
- Confirmed identification, ruling out look-alikes.
- A RICS-style risk category and a clear written report.
- A recommendation, and a costed management plan where treatment is advised.
What it costs
A survey and report typically costs in the region of £150–£350. The exact figure depends on the size of the site, access and how detailed the report needs to be for your lender. This is separate from the cost of any treatment that follows — a herbicide programme usually runs to several thousand pounds over a few seasons, and excavation considerably more. See survey cost in detail and removal cost.
| Stage | Typical cost |
|---|---|
| Survey and report | £150–£350 |
| Herbicide programme (3 seasons) | £1,500–£3,000 |
| Excavation / dig-and-dump | £5,000–£15,000+ |
How to book the right surveyor
The accreditation that lenders and solicitors trust is the Property Care Association (PCA). A PCA-accredited member works to recognised standards and can offer an insurance-backed guarantee on treatment — the combination that usually satisfies a mortgage lender. Ask whether the report will state a RICS management category and whether an insurance-backed guarantee can be provided.
Your next step
Book a PCA-accredited surveyor, keep the stand undisturbed, and gather any paperwork from previous owners. With the report in hand you can move a sale forward, respond to a lender, or plan treatment with confidence. If a mortgage is the driver, read knotweed and mortgages next.
Book a PCA-accredited survey now
Arrange an inspection with an accredited specialist. You’ll get a written report with a RICS risk category and a clear recommendation — everything a lender or solicitor needs.
Frequently asked questions
How quickly can I get a survey done?
Many specialists can inspect within a week or two, with the written report following a few working days after the visit.
Will the survey tell me what treatment I need?
Yes — where knotweed is found, the report recommends an approach and a specialist can provide a costed management plan.
Is a cheaper survey as good?
What matters is that the surveyor is PCA-accredited and the report states a RICS risk category; that is what lenders accept, not the headline price.
Do I need a survey if I’m not selling?
If knotweed is established it is worth surveying and treating early; it spreads and becomes more costly to deal with the longer it is left.
Sources & further reading
- Property Care Association (PCA) — find an accredited invasive weed specialist
- RICS — Japanese Knotweed and Residential Property guidance note (2022)
- Environmental Protection Act 1990 — controlled waste duty of care
- GOV.UK — Prevent Japanese knotweed from spreading
This guide is general information, not a site-specific survey or legal advice. Japanese knotweed treatment and removal should be assessed by a PCA-accredited specialist before you act.