RP19: First flush rainwater diverters and downpipe filters
Source: gov.uk (2025-02-03)

Find out about eligibility and requirements for the first flush rainwater diverters and downpipe filters item.

This item is part of Capital Grants 2025. You must read the Capital Grants 2025 guidance (https://www.gov.uk/government/publications/capital-grants-2025) to understand the rules and how to apply. If you’re applying for this item as part of a Countryside Stewardship Higher Tier (CSHT) application, you must read the CSHT applicant’s guide (https://www.gov.uk/government/publications/countryside-stewardship-higher-tier-csht) to understand the rules and how to apply.

How much you’ll be paid

£174.59 per unit.

How this item benefits the environment

This item filters potentially contaminated roof water to keep leaves, debris and other contaminants out of diverters, clean water drains and water storage tanks.

This provides water that you can use around the farm for different purposes such as:
- filling and washing down pesticide sprayers
- livestock drinking
You can use this water instead of wasting potable water supplies.

This item can help you protect, recover and improve biodiversity on your land.

Where you can use this item

You can only use this item with support from Catchment Sensitive Farming (https://www.gov.uk/guidance/catchment-sensitive-farming-reduce-agricultural-water-pollution):
- in areas targeted for the reduction of water pollution from agriculture
- with a rainwater harvesting system
Catchment Sensitive Farming provides advice where there are water quality or flood risk issues linked to farming.

What you must do to use this item

You must:
- follow manufacturer’s guidelines to install individual rainwater diverters and filters, wall-mounted diverters or stand-alone diverters – the exact items installed will depend on the volumes of water that need treating
- make sure that contaminated water is not diverted to a clean water drain or discharged to ditches or watercourses
You must also check if restrictions apply to using harvested rainwater in your supply chain. Check with your relevant farm assurance scheme and purchasers of your produce to confirm.

Evidence you must keep

You must keep written support from your Catchment Sensitive Farming adviser and provide with your application.

You must also keep photographs of the completed work and provide with your claim.

You must also keep and provide on request:
- any consents or permissions connected with the work
- receipted invoices or bank statements where a receipted invoice is unavailable
- photographs of site before works start
Read the record keeping and site visit requirements in the Agreement holder’s guide: Capital Grants, Higher Tier capital grants and Protection and Infrastructure grants (https://www.gov.uk/government/publications/agreement-holders-guide-capital-grants-higher-tier-capital-grants-and-protection-and-infrastructure-grants-2025) for more information.

If you’re applying for this item as part of a Countryside Stewardship Higher Tier (CSHT) application, read the record keeping and site visit requirements in the CSHT agreement holder’s guide (https://www.gov.uk/government/publications/countryside-stewardship-higher-tier-csht).

Other items you can use with this item

You can use this item with these items:

RP16: Rainwater goods (https://www.gov.uk/countryside-stewardship-grants/rainwater-goods-rp16)

RP17: Storage tanks underground (https://www.gov.uk/countryside-stewardship-grants/storage-tanks-underground-rp17)

RP18: Above ground tanks (https://www.gov.uk/countryside-stewardship-grants/above-ground-tanks-rp18)

Advice to help you use this item

The following advice may help you to use this item, but you do not have to follow it to get paid. It’s not part of this item’s requirements.

British Standards

Check to make sure the work meets relevant British Standards (https://www.bsigroup.com/en-GB/products-and-services/standards/).

Improving water quality

To improve water quality around the farm:
- collect rainwater from roofs and buildings and use it for tasks around the farm such as yard washing – fitting a first flush rainwater diverter is critical to good quality water
- know that water diverters improve water quality, reduce tank maintenance and protect pumps by preventing the first flush of water which may contain contaminants from the roof entering the tank
- use downpipe filters to keep leaves, debris and other contaminants out of diverters, clean water drains and water storage tanks – the work includes the supply and installation of downpipe filters
Historic and archaeological features

You may need advice if you want to install the item close to a historic farmstead or listed building. You can get advice on listed building consent from your local authority.

You should consider the effect of the item on the:
- historic building itself
- the historic building’s location
- the nature and historic value of the land where the building is located
Effective use of water on dairy farms

Read about the effective use of water on dairy farms on the Agriculture and Horticulture Development Board (AHDB) website (http://dairy.ahdb.org.uk/technical-information/environment/water-use/).