Slurry Storage Required Calculator
Instantly calculate your minimum slurry storage requirement
5 or 6 month NVZ rule • RB209 accurate
Minimum Storage Required
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m³
Equivalent in UK Gallons
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gallons
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UK Slurry Storage Calculator: Meet NVZ Requirements in 2025/26
Free RB209-accurate tool to calculate your minimum slurry storage needs. Instant results in m³ and UK gallons – with downloadable PDF reports for compliance records.
Why Slurry Storage Calculations Matter for UK Farmers
Under the Nitrates Pollution Prevention Regulations (NVZ rules), UK farmers must store enough slurry to cover 5 months (most areas) or 6 months (designated NVZ zones) without spreading during closed periods. Getting this wrong risks fines up to £5,000 per breach, plus costly tank upgrades.
Our free Slurry Storage Calculator uses official RB209 data from AHDB to give you precise minimum requirements. Enter your livestock numbers, select your NVZ rule, and get instant results – plus a one-click PDF for your farm records.
How to Use the AgriOps Slurry Storage Calculator
- Add Your Livestock: Click "Add Livestock Type" and select from 20+ RB209 categories (dairy cows, beef cattle, sheep, etc.). Enter the number of head for each group. You can add unlimited rows for mixed herds.
- Select NVZ Rule: Choose 5 months (standard UK) or 6 months (NVZ zones like parts of East Anglia or Yorkshire). The tool auto-adjusts calculations.
- Get Instant Results: See your minimum storage in cubic metres (m³) and UK gallons. Based on average weekly production rates × head × months × 4.345 weeks/month.
- Download PDF Report: Enter your email (optional) for a professional landscape PDF with breakdowns, totals, and compliance notes. No spam – we hate it too.
RB209 Slurry Production Rates: Weekly m³ per Head
These are the official AHDB RB209 Table 2 rates used in our calculator. Rates assume typical UK conditions and include dilution for clean water (adjust if your system differs).
| Livestock Type | Weekly Slurry (m³/head) |
|---|---|
| Dairy cow (over 9000 litre milk yield) | 3.1 |
| Dairy cow (6000 to 9000 litre milk yield) | 2.8 |
| Dairy cow (up to 6000 litre milk yield) | 2.5 |
| Dairy heifer replacement (13 months to first calf) | 1.8 |
| Dairy heifer replacement (3 to 13 months) | 0.9 |
| Beef suckler cow (over 500kg) | 2.3 |
| Beef suckler cow (up to 500kg) | 2.1 |
| Steer/heifer (over 25 months) | 1.6 |
| Steer/heifer (13 to 25 months) | 1.5 |
| Steer/heifer (3 to 13 months) | 0.7 |
| Bull beef (3 months and over) | 1.4 |
| Bull for breeding (over 25 months) | 1.2 |
| Bull for breeding (3 to 25 months) | 1.1 |
| Calf (up to 3 months) | 0.3 |
| Ewe (<60 Kg / Lamb under 6 months) | 0.07 |
| Ewe (>60 Kg / Lamb under 6 months) | 0.09 |
| Ewe/Ram (Dry) | 0.09 |
| Lamb (6 to 9 months) | 0.04 |
| Lamb (Over 9 months) | 0.05 |
| Other Livestock | 0.7 (default) |
Source: AHDB RB209 (2025 edition). Rates are for dilute slurry (8–10% dry matter). Adjust for your farm's dilution rate if needed.
How to Apply Your Slurry Storage Results
Once calculated, compare against your current tank capacity (use our Slurry Tank Capacity Tool for exact available volume, including freeboard).
- Check Compliance: Required m³ must be ≤ your available tank space. Add 10–20% buffer for rainfall/dirty water.
- Plan Upgrades: If short, quote new tanks (e.g., 1,000 m³ fibreglass ~£15k–£25k). Apply for grants via DEFRA's Farming Investment Fund if eligible.
- Record Keeping: Save your PDF – it's NVZ audit-proof. Update annually for herd changes.
- Closed Periods: No spreading Oct 1–Jan 31 (5 months) or Nov 1–Feb 28 (6 months) in England/Wales. Scotland/NI rules differ slightly.
Pro Tip: Pair with our Slurry N+P Calculator to plan spreading rates and avoid over-application fines.
Frequently Asked Questions: Slurry Storage & NVZ Rules
Do I need this if I'm not in an NVZ?
Yes – all farms producing >5,000 kg N/year (most livestock farms) must follow storage rules. Check your NVZ status on GOV.UK.
Is this calculator for England only?
It's England/Wales compliant (DEFRA rules). Scotland uses similar RB209 but check SEPA; NI via DAERA. Rates are universal.
What if my slurry is more/less dilute?
RB209 assumes 8–10% DM. For drier slurry, divide calculated m³ by 1.2–1.5. Test yours via lab analysis.
Can I export manure to reduce storage?
Yes – deduct exported N (use our NVZ Checker). Keep receipts for audits.
How often should I recalculate?
Annually, or after herd changes. Closed periods start soon – run it now for 2025/26.