Japanese knotweed removal costs

The Property Care Association's guideline figures, published in December 2022, put a residential herbicide programme for 1 to 25 m² at £2,000 to £4,000, and full excavation at £3,000 to £6,000 for 1 m² or £8,000 to £16,000 for 10 m². These ranges are indicative; the price for a given property depends mainly on the method, the size of the stand, access and how much soil has to be taken away.

Guideline prices

The PCA set out these figures in its guidance for valuers and surveyors, as a guideline for mortgage valuation only.

The PCA says site-specific constraints can push costs above these ranges, and does not state whether the figures include VAT.

What affects the cost

Herbicide is the cheaper of the two main methods in the PCA table, and Dr Daniel Jones told the House of Commons Science and Technology Committee that excavation is "an order of magnitude greater in cost" than herbicide. Size matters too, although RICS warns that visible growth is not a definitive guide to the full extent of an infestation or the cost of dealing with it. The PCA also cites access as one reason for the spread in its excavation and root barrier ranges.

Checkatrade, a cost-guide site, adds nearby watercourses, distance from habitable space, backing onto Network Rail land and encroachment to or from neighbours. It notes that some lenders want a five-year plan and guarantee, and RICS says a guarantee should run for at least five years after completion and be backed by insurance. Fantastic Services, which sells the service, says London and the South East add roughly 20 to 30%.

Excavation and soil volume

RICS says excavation typically extends 2 to 3 metres beyond the edge of the visible stand and 1 to 2 metres deep, and gives this worked example.

At those volumes, even a small infestation can cost several thousand pounds in waste charges alone, covering excavation, transport and Landfill Tax, according to RICS. It adds that on-site burial or stockpiling may cut waste costs on large sites but is unlikely to suit standard residential properties.

Disposal charges and Landfill Tax

In its report of 16 May 2019, the committee quoted RICS figures for disposing of excavated material: £25 to £50 per tonne at December 2011 prices, or £30 to £60 in 2018 money. Those figures exclude Landfill Tax and are now several years old.

HMRC's Landfill Tax rates for England and Northern Ireland changed on 1 April 2026.

The rate for knotweed soil

HMRC's general guide to Landfill Tax does not mention knotweed. Naturally occurring soils qualify for the lower rate only if they neither contain nor are contaminated with any material outside the list in the 2011 Qualifying Material Order. Sub-soil is on that list but topsoil is not, and loads described only as "soils" should be standard-rated unless there is evidence they are entirely sub-soil. We have found no HMRC guidance confirming which rate applies to knotweed waste, so ask each specialist which rate their quote assumes.

Herbicide costs

The committee also quoted an RICS estimate, at December 2011 prices, of £2,000 to £5,000 in total for herbicide treatment at a typical three-bedroom semi-detached house, which it put at £2,400 to £6,000 in 2018 terms. The PCA's December 2022 guideline is more recent.

Herbicide is a multi-year programme: RICS says it needs at least four years of treatment and monitoring before a completion certificate, and the PCA describes two years of each. Where a lender is involved, RICS looks for the costs to be paid upfront by the current owner.

Council treatment prices

Neath Port Talbot Council in Wales publishes prices for its own treatment service, all including VAT. The page is undated; we checked it in October 2026.

For micro sites up to 4 m², the five yearly payments are £303.09, £168.39, £168.39, £134.68 and £134.68, a total of £909.25. Larger sites receive a bespoke quote at the domestic charges plus £118.86 an hour for extra time on areas over 50 m².

The council offers no insurance-backed guarantee, does not deal with neighbour disputes or take legal action, and requires payment in advance. It is therefore a low-cost benchmark rather than a typical specialist price. That matters when buying, selling or remortgaging: for RICS Categories A and B, RICS anticipates most lenders will expect a management plan with an insurance-backed guarantee.

Commercial price guides

Ranges from cost-guide sites and companies are not trade body figures and vary widely, so use them only as a rough cross-check.

Checkatrade calls its figures ballpark averages and says dig-and-dump costs around ten times as much as herbicide, but does not disclose its data source or sample size. MyJobQuote does not say whether its figures include VAT. Fantastic Services says its figures include VAT where applicable. Its herbicide range is well below the PCA guideline, and it is the only published source we found for survey and guarantee prices, so treat those two figures with particular care.

Comparing quotes

Quotes for the same stand can differ in method, in how the infestation is measured and in what is included: one may cover waste, Landfill Tax, backfilling, monitoring visits, a management plan and a guarantee while another omits some of them. VAT treatment and guarantee length vary too, and the PCA says completion is normally combined with a guarantee covering regrowth for 2, 5 or 10 years.

To make quotes comparable, ask each specialist to:

1. carry out a survey that measures each stand and shows it on a scaled plan, as RICS expects in a management plan
2. name the method they recommend and explain the choice
3. itemise the price: survey, each year of treatment, monitoring visits, excavation, transport, disposal, Landfill Tax, backfilling and the guarantee
4. state whether VAT is included or shown separately
5. set out the guarantee's length, whether it is insurance-backed and whether it transfers to a buyer
6. confirm their trade body membership, which you can check for yourself

Prices are set by each specialist, and any survey, quotation or work is agreed directly with the specialist you choose.