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Nitrate Vulnerable Zones control fertiliser and manure use on farmland to protect water quality. Search a UK location to check NVZ status, closed periods and application limits.
Updated: reviewed periodically by DEFRA · Last checked by Maplify: July 2026
This layer maps Nitrate Vulnerable Zones (NVZs), designated where surface waters are eutrophic or at risk of eutrophication from agricultural nitrate, or where groundwater nitrate concentrations approach or exceed the 50mg/l drinking water limit. Around 58% of England's agricultural land is designated NVZ.
Excess nitrogen leaches through soil into rivers and groundwater, causing algal blooms and oxygen depletion in water bodies and posing health risks in drinking water — the reasoning behind NVZ spreading rules.
NVZ status directly controls when and how much fertiliser or manure can be applied to farmland, with closed periods and application limits that affect farm operations and require adequate manure storage capacity. Farmers and land managers check this layer before purchasing or leasing agricultural land to understand compliance obligations.
Because NVZs frequently overlap with Source Protection Zones, checking both together gives a fuller picture of the water protection restrictions applying to a specific parcel of farmland.
NVZ designated land
Closed periods and nitrogen application limits apply — around 58% of England's agricultural land.
Closed period
Set dates when spreading nitrogen fertiliser or manure is prohibited, varying by land use and nitrogen type.
The table below summarises the closed periods for spreading organic manures and manufactured nitrogen fertiliser within an NVZ.
Grassland
15 September – 15 January, all organic manures
Tillage (high readily-available N)
1 September – 15 January
Tillage (other organic manures)
1 October – 15 January
All land
15 October – 15 January, manufactured nitrogen fertiliser
The standard nitrogen application limit from organic manures is 250kg N/ha/year, and NVZ rules generally require a minimum of 6 months storage capacity for cattle slurry and 4 months for pig slurry.
Confirm current NVZ designation directly with DEFRA before completing a land purchase or lease.
Review closed period dates and nitrogen application limits applicable to the specific land use.
Assess existing manure storage capacity against the 6-month (cattle) or 4-month (pig) NVZ requirement.
Check the Source Protection Zones layer for the same land, since these designations frequently overlap.
Consult an agronomist for a full compliance assessment specific to the holding.
This is general guidance, not professional or legal advice — confirm specifics with the relevant authority or a qualified professional.
Farmers & Land Managers
Confirm closed periods and application limits before spreading fertiliser or manure.
Agricultural Land Buyers
Check NVZ compliance obligations before completing a purchase.
Environmental Consultants
Advise on manure storage and nutrient management planning.
Solicitors
Flag NVZ status during agricultural land conveyancing.
NVZ checks for farmland are commonly combined with these related searches.
What is a Nitrate Vulnerable Zone?
An NVZ is an area designated by DEFRA where agricultural nitrate pollution threatens drinking water quality or causes eutrophication of surface waters. Around 58% of England's agricultural land is designated NVZ.
What are NVZ closed periods?
Closed periods are set dates when spreading nitrogen fertiliser or manure is prohibited because crops can't use it. They typically run from September to mid-January depending on land use and nitrogen type.
How much manure storage capacity do I need in an NVZ?
NVZ rules generally require a minimum of 6 months storage capacity for cattle slurry and 4 months for pig slurry, with impermeable, compliant storage structures.
What is the nitrogen application limit in an NVZ?
The standard limit from organic manures is 250kg N/ha/year, or a lower limit for grassland farms under specific derogation criteria.
Do NVZs overlap with Source Protection Zones?
Yes, often. Where they overlap, both sets of restrictions apply — check both layers together for agricultural land near a drinking water source.
Search any UK location to see Nitrate Vulnerable Zone status alongside water and environmental data.
| Provider | DEFRA / Environment Agency |
| Geometry type | Polygon |
| Coverage | England |
| Update schedule | Reviewed periodically; designations change infrequently |
| Reference date | July 2026 |
| Licence | Open Government Licence v3.0 |
