What a Wohngeldbehörde Decides, and Why It Is a Law-as-Code Problem

By the end of this chapter you will know what one family in Weimar receives, which sections decide it, and why “how much” and “is it owed” are two different questions.

Lawyer: which § decides each answer.
Analyst: which fact flips the answer.
Developer: which command reproduces it.

1. The benefit and the authority

Wohngeld is Germany’s housing benefit: a monthly subsidy towards housing costs for households whose income is too high for basic income support but too low to carry the rent alone. The federal Housing Benefit Act — the Wohngeldgesetz, WoGG — sets the conditions and the formula. A federal ordinance, the Wohngeldverordnung (WoGV), sorts every municipality into a rent level. The amounts themselves are fixed in three annexes to the Act, the Anlagen, which the federal government updates every second year.

The decision is made locally. A Wohngeldbehörde — the housing-benefit office of a district or city — receives the application, establishes the facts and issues the decision notice, the Bescheid. The federal ministry responsible for housing, the BMWSB, keeps the Act and its annexes up to date and publishes worked examples of the calculation.

There are two kinds of Wohngeld. A Mietzuschuss helps tenants; a Lastenzuschuss helps owner-occupiers with the costs of their own home. This book follows tenants.

2. One family, one question

Meet the Vogts — a fictional family whose facts are those of the ministry’s official example: Rechenbeispiel 7 in the BMWSB brochure Beispiele für die Berechnung des Wohngelds, as of 1 January 2025. The names are ours; the numbers are the ministry’s.

Family card
Household	Katrin and Markus Vogt, married; Lena (10) and Paul (6)
Home	a rented flat in Weimar, Thuringia
Rent	€580 a month, without heating (Bruttokaltmiete)
Income	Katrin earns €2,240 gross a month; nobody else in the household has income
Date of the question	1 January 2025
Still open	nothing — the authority has assessed everything it must assess

The ministry’s example gives the children no ages; the case records 10 and 6, which do not affect the amount.

Their question: how much Wohngeld do we receive from January 2025, and on which basis?

Before you read on, make a prediction. The ministry’s example was published for 1 January 2025. Would the same family, with the same rent and income, have received more, less or the same on 31 December 2024?

Question	Model’s answer (recorded 12 October 2026)	Section
Monthly assessed income	€1,710.00 — established	§ 13 Abs. 2, §§ 14–16 WoGG
Rent taken into account	€777.80 — established	§ 11 Abs. 1, § 12 Abs. 1, 6, 7 WoGG
Monthly Wohngeld by the formula	€485 — established	§ 19 WoGG with Anlagen 2 and 3
Claim to €485	established	§§ 19–21 WoGG
The same family on 31 December 2024	€463 — established	§ 44 Abs. 1, § 43 WoGG

The ministry’s 2025 example gives the first three numbers — €1,710.00, €777.80 and €485 — and the model matches them to the euro. The last line applies the values in force on 31 December 2024 to the same facts and gives €463; it answers your prediction: the family would have received €22 less. Nothing about the family changed; the law did, overnight, and the Act itself says which text to use on which day. Chapter 1 is about exactly that.

3. Five kinds of answer

A housing-benefit office does not give one kind of answer. The model keeps five apart, because confusing them is how people are wronged:

Answer	When	What the model returns
An amount	every premise is established	the amount, established, with the path through the sections
No claim by law	an excluding fact is established — another benefit that covers housing costs, an amount under €10	a ground of exclusion, established
Not enough facts	the rent level, the rent, a member’s status or an income is missing	not established — no amount, and not zero
The authority must assess	the Act leaves a judgment to the office: whether claiming would be abusive (§ 21 Nr. 3), whether two people form a community of responsibility “nach verständiger Würdigung” (§ 5 Abs. 1 S. 2 Nr. 3)	a request addressed to the Wohngeldbehörde
Outside the model	a Lastenzuschuss, or a kind of income the model does not cover	a flag naming why there is no number

The third and fifth lines matter most to a family. “We do not have your rent yet” is not “you get nothing”, and “our model does not cover owner-occupiers” is not “the law gives you nothing”. Chapters 6–8 take these answers one by one.

4. What an answer contains

Every answer from the model carries four things:

the facts used — the family’s data, each with its origin: entered by the household, or decided by an authority;
the parameters applied — rent ceilings, heating relief, the formula’s values — each tied to the row of the Anlage that was in force on the date, and to the issue of the Bundesgesetzblatt (BGBl), the federal law gazette, that published it;
the operations — a proof graph, rule by rule, from the facts to the result;
the section behind each rule, in the edition in force on the date of the question.

German administrative law asks for the same things in its own words. A written decision must state its essential factual and legal grounds (§ 35 Abs. 1 SGB X). A decision may be issued fully automatically only where there is no reason to have an official handle the individual case (§ 31a SGB X). The model shows what an answer rests on; it does not by itself make a decision lawful.

5. Why this is a law-as-code problem

The Vogts’ €485 draws on the WoGG, the WoGV with its list of rent levels, the Income Tax Act (EStG) for the definition of income, two amending ordinances and an amending Act. On top of that:

the text changes on a fixed date — every second year, the annexes are replaced, and § 44 says the new values apply from that day;
the model’s values run out — the model holds annex values for dates up to 31 December 2026; the next ones are not yet enacted, and the model must not invent them;
some conditions need the office — the Act leaves “abusive” and “nach verständiger Würdigung” to the authority;
some facts come from other authorities — whether a member receives basic income support with housing costs is decided by a job centre, not by the formula;
one amount, many readers — the household, the caseworker, the auditor and the court must all be able to follow it.

6. Standing on German shoulders

This book builds on German work that is older than the phrase “law as code” — the civil code’s systematic order, Rechtsinformatik since 1970, free federal law online, the ministry’s own worked examples, GETTSIM and, beyond Germany, Catala. The acknowledgements give each of these its due.

7. What this book adds

New to law as code? Skim this table now and come back to it after Chapter 3.

In Arxo	Chapter
The date of the question selects the edition and the row of each Anlage, and the answer names both	1, 9
Past the last values this model holds, the answer is a refusal with a reason, not zero	1, 8
A missing premise the model checks is not established; it is not treated as “no”	2, 8
A question the Act leaves to the authority becomes a request addressed to the Wohngeldbehörde, while the amount is already known	6
An exclusion rests on another authority’s decision entered as a fact, with its origin	7
Two records that disagree give a contradiction status, kept for review	8
A saved answer can be replayed from its fingerprints, byte for byte	9

Catala’s strengths come first wherever the book compares: exact decimals, money and dates, exceptions written beside the text, tests and execution traces. Appendix F names the version and the date of the check, once for all comparisons.

8. A few German terms

German	English	Meaning in this book
Wohngeld	housing benefit	the monthly subsidy this book follows
Mietzuschuss / Lastenzuschuss	rent subsidy / owner-occupier subsidy	the tenant’s and the owner’s kind of Wohngeld; the second is outside the model
Wohngeldbehörde	housing-benefit authority	the local office that decides
Bescheid	decision notice	the written decision the household receives
Haushaltsmitglied	household member	a person whose income and needs count
Bruttokaltmiete	gross rent without heating	the rent including service charges, excluding heating and hot water
zu berücksichtigende Miete	rent taken into account	the rent the formula uses, after ceilings and heating relief
Mietenstufe	rent level I–VII	the level of rents in a municipality, set by the WoGV
Gesamteinkommen	assessed household income	income as the WoGG defines it, not as a payslip shows it
Fortschreibung	biennial update	new values in the annexes every second year
Anlage	annex	the tables of amounts attached to the Act
Bundesgesetzblatt (BGBl)	federal law gazette	where Acts and ordinances are published

9. Explore the case

All answers in this chapter come from one case package, familie-weimar, which holds four files over the same model. The commands below are patterns: <case package> stands for the path of that package in a checkout of the Arxo repository, given in full in the appendix on reproducing the examples.

law ask <case package> --case Familie2025 --query-json queries/wohngeld-485.json
law ask <case package> --case Familie20241231 --query-json queries/wohngeld-463.json

The first asks whether the monthly Wohngeld on 1 January 2025 is €485; the second asks the same family’s question on 31 December 2024 with €463. Chapter 3 shows what comes back. These answers were recorded on 12 October 2026 with law 0.1.12.

Exercise

Use the table in section 2 and the five kinds of answer in section 3.

The office has the Vogts’ income but not yet their rent. Which kind of answer does the model give for the monthly Wohngeld, and why is it not €0?
Which amount in section 2 changes between 31 December 2024 and 1 January 2025, and which calculated inputs stay the same?
A colleague says: “The formula gives €485, so the family has a claim to €485.” What else must hold?