On 15 October 2026, the Government formally declared severe drought in parts of West Sussex, including the Arun Valley.

Pulborough, the Arun Valley and wider West Sussex are entering one of their driest periods in decades, according to new Government and Environment Agency data.

Reservoir stocks, river flows and soil moisture levels across the South Downs and Arun catchment have all fallen sharply, prompting stepped‑up drought planning and a call for residents to use water wisely.

The Local Picture: Arun Valley & Pulborough

The latest Solent and South Downs Water Situation Report (September 2026) shows:

• Arun hydrological area rainfall: 35mm — just 54% of the long‑term average (66mm). This makes July–September the driest three‑month period on record for the Arun and Western Rother Greensand units.
• Soil moisture: All hydrological areas ended September drier than average, increasing pressure on groundwater recharge.
• River flows: Monthly mean flows ranged from exceptionally low to normal, with the Arun catchment among the worst affected.
• Reservoir stocks: Ardingly Reservoir (Ouse) is at 22.8% of its long‑term average, and Arlington Reservoir (Cuckmere) at 35.5% — both significantly below normal.

For Pulborough, this matters. The Arun’s tidal reach, clay soils and low‑flow conditions increase the risk of water scarcity, habitat stress, and reduced resilience heading into winter.

What this means:

• Customer supplies remain uninterrupted, but water companies must take proactive measures to safeguard future availability.
• Daily monitoring of reservoir and river levels is now mandatory.
• The Environment Agency will conduct tougher compliance checks on businesses abstracting water.
• Local Resilience Forums have been activated to coordinate support if conditions worsen.

Environment Secretary Dame Angela Eagle said:

“This level of drought is something we have not experienced for decades, so this government is stepping up our support and planning. We are working closely with water companies to protect public supplies… and I’d continue to urge everyone to think about how they can use water wisely over the coming weeks.”

Water Minister Emma Hardy added:

“We are prioritising protecting public water supplies in areas affected by severe drought… allowing water companies to keep more water in depleted reservoirs where necessary.”

England‑wide Water Resource Pressures

The Government has declared severe droughts in parts of Cornwall, Devon, Dorset, Somerset, East and West Sussex.

National drought reports show the broader context:

• Reservoir storage across England: 54% — 21% below average for October. Nineteen reservoirs are under 50% full, eight “exceptionally low”.
• River flows: Over half of monitored sites remain normal or lower, despite slight recent rainfall.
• Temporary Use Bans (hosepipe bans): Affecting millions, including customers of South East Water in Sussex.
• Agriculture: Reduced crop yields, early harvesting and pressure on winter forage stocks. Over 1,353 abstraction licence restrictions are in place.
• Environmental impacts: Low flows, algal blooms, fish deaths and wildfire risk continue to rise.

Implications for Pulborough & the Arun Valley

• Local risks
• Lower Arun flows increase stress on wetland habitats at Pulborough Brooks.
• Groundwater decline affects rural properties relying on boreholes.
• Agricultural pressure is felt across the Arun floodplain, with livestock farmers already using winter forage.
• Navigation impacts may affect the Wey & Arun Canal Trust’s restoration sections.

Community resilience

Pulborough’s ongoing work on riparian responsibilities, drainage maintenance and emergency planning aligns closely with Government drought-readiness actions.

How Residents Can Help

• Use water wisely
• Reduce garden watering and car washing.
• Check for leaks in domestic plumbing.
• Use water‑efficient appliances and short showers.

Report issues

Low river flows, fish in distress, or environmental concerns:

• Environment Agency incident hotline: 0800 80 70 60

Water supply problems or leaks:

• Contact your water company (South East Water or Southern Water depending on location).

Explainer: Arun Catchment: Rainfall & Reservoir Levels

Overview

The Arun catchment — stretching from the High Weald through the Rother valley and down to Pulborough, Amberley and Arundel — is experiencing exceptionally low rainfall and declining water storage. Government and Environment Agency data show that the 2026 dry period is now one of the most severe in decades.

This explainer outlines where rainfall deficits are concentrated, which reservoirs are under pressure, and how this affects communities in Pulborough and the Arun Valley.

1. Rainfall Across the Arun Catchment

• High Weald headwaters (north of the catchment): Rainfall at 35mm, around 54% of the long‑term average. This is the primary source region for the Arun and Western Rother — meaning deficits here directly reduce river flow downstream.
• Greensand Belt (Billingshurst → Pulborough → Coldwaltham): July–September 2026 is the driest three‑month period on record for this hydrological unit. Soil moisture is “much lower than average”, limiting groundwater recharge.
• South Downs fringe (Amberley → Arundel): Rainfall slightly higher but still below average; tidal influence means low upstream flows have a disproportionate impact.

Local interpretation

Pulborough sits at the tidal limit of the Arun. When upstream rainfall is low, the river becomes more vulnerable to:

• Tidal lock
• Reduced freshwater inflow
• Habitat stress at Pulborough Brooks
• Lower resilience heading into winter

2. Reservoir Levels in West Sussex

Although the Arun catchment itself has no major public‑supply reservoir, regional storage determines supply security for Pulborough and surrounding villages.

Key reservoirs supplying West Sussex

• Ardingly Reservoir (Ouse catchment): 22.8% of long‑term average — significantly below normal.
• Arlington Reservoir (Cuckmere catchment): 35.5% of long‑term average — also well below expected levels.
• Weir Wood Reservoir (Medway catchment): Lower than average but not yet critical.

Key Points

• Downward trends in storage despite intermittent rainfall
• Pressure on inter‑catchment transfers that support West Sussex supply zones
• Local interpretation
• Pulborough residents rely on regional water‑resource balancing, meaning:
• Low reservoir stocks elsewhere directly affect supply resilience here
• Water companies may increase abstraction from rivers and groundwater, adding pressure to the Arun system
• Temporary Use Bans (hosepipe bans) may be extended or reintroduced

4. What This Means for Pulborough

Local impacts

• Wetland stress at Pulborough Brooks
• Lower river flows increasing risk of algal blooms
• Pressure on borehole supplies for rural properties
• Higher wildfire risk on the Downs
• Agricultural strain across the Arun floodplain
• Community preparedness

Pulborough’s existing resilience work — riparian responsibilities, drainage maintenance, and emergency planning — aligns with Government drought‑readiness actions.